Oyster Reef Ecosystem Tank

[Subsea]

Awesome biotheme

Awesome biotheme

I have some updates on my 20g long. The Ulva is pretty much gone. I'm not sure that the parameters are right from growing macros in this tank (light, etc.), plus, I'm sure that the shrimp and crabs eat some of it. I probably won't add much until I get the main tank set up. I can't tell of the other macro is growing or not. There are some parts that seem to, and others I'm not so sure about. It looks good in the tank still, and provides good cover for the smaller fish, so I'm leaving it in there. The sea grasses have died off, so that experiment ends until I get the main tank set up. I have some cyanobacteria and some green hair algae areas on shells and sand where the most light hits that could be competing with the macros and seagrass for nutrients. Right now, I'm not too worried about this but would like to figure it out prior to setup of the main tank. We will see how that goes. I personally don't think it looks that bad as it still adds color, plus, the crabs and shrimp seem to eat it.

Both colonies of bryozoans are expanding across the tank glass on either end of my tank, in the darker areas. They look cool.

One thing that came in handy was the purchase of an automatic feeder to keep my fish fed while I was away on vacation. We couldn't find anyone reliable that new much about fishkeeping, so this was my solution. It worked out OK. The only issue that I anticipated was if the fish would actually adapt to and eat flake food or pellets, since, up until my trip, all they've eaten were live or frozen foods for the most part. My attempts at feeding them flakes were with mixed results. The gobies ate flakes with gusto. Some of the blennies ate the flakes, ingesting some or spitting out some, and other blennies ignored the flakes. The skilletfish ate flakes at times, but not often.

As far as pellets go, they were a little too big for most of my fish, and for the ones that tried to eat them, they spit them out at first and later kept attacking them until they were bite sized enough to eat them. The blennies broke them up and ate some, and then the gobies would follow behind and eat some of the fragments, while the skilletfish ignored the pellets altogether.

So, I made the decision to go with flakes in the auto feeder. I had no other choice.

After returning from my trip, I noticed that all of the fish will eat flakes now. Gobies still eat them with gusto, as do the blennies if they're hungry. If the blennies aren't hungry, they ingest them and sometimes eat some of the "flavors" while spitting out others. Skilletfish will eat flakes at times, but not that much.

The gobies and blennies all grew and are all fatter than fat. A couple of the gobies grew almost a 1/2" while we were gone (about 10 days), which I thought was amazing.

Also, I thought that I had only two crabs in the tank, but as it turns out, there are three of them. I've identified two of the crabs as the white-clawed mud crab, a.k.a. the Harris mud crab (Rhithropanopeus harrisii). I'm not sure of the third crab species as it looks different, but, I really haven't had a good look at them. Until now, the crabs have been hiding mostly. Recently, two of them come out during feeding time, and one of those is out foraging even while not feeding. In fact, last night, it was moving all over one of the oyster reef structures all the way to the water's surface.

From what I've read, they only grow to about an inch or so, and they aren't aggressive toward fish or shrimps. I'd bet they'd eat them if they could catch them, but, so far, I've seen blennies actually land on them and the crabs just move away. They raise their claws if fish near them, but so far, haven't tried to grab any fish. The shrimp seem to be good at avoiding them. I also read that these crabs feast on all types of snails. I don't have snails in my tank at the moment, but if I add them, these will have to be stocked often to keep a population of them.

Here are a couple videos of my tank.

The first one pretty much follows the largest blenny of the tank:
https://youtu.be/mBe7XgwgZ-M

I tried to view the tank in general with this video, bouncing from one fish to another:
https://youtu.be/dc_YRaTyF0s

Hope you all like them.

Awesome vidio! The translucent grass shrimp rock. They are very brave to swim in the open like that. Did you blue to oyster structure together. I like it. My first marine aquarium was a Galveston Bay biotheme. I gathered a large oyster cluster that took up 1/3 of a 55G tank. No live oysters, but numerous barnecles that would sweep the water with their 1/2 fans. That was in 1971 and I have been addicted every since.

 

[Subsea]

Dynamic Equilibrium

Dynamic Equilibrium

I have an update for my oyster reef "system". The 20g long that started this thread is still going strong, with 6 small striped blennies, 5 small skilletfish, 5 naked gobies, two new juvenile killifish (probably juvenile mummichogs), 3 white-clawed mud crabs, an unidentified harmless isopod, a bunch of grass shrimp, and red macroalgae. All of the fish are fat and healthy. I tried to add three silversides but that didn't work out. They made it home just fine, which is what worried me the most. They were about 2 1/2" long and looked great in the tank, until the 2" clingfish killed and ate the first one. Another one was harrassed by the blennies and died, then devoured by the gobies and a crab. And the last one died of unknown causes during the night, probably killed by the same culprits. The only issue with the tank is that with the heavy bioload and feeding, cyanobacteria growing some pretty large patches. I don't think it looks necessarily bad, but I'd rather have those nutrients consumed by Ulva which hasn't done well in this tank.


The 20g high tank that I was using as a holding tank is now set up as a display also. I added a large artificial oyster cultch that I built for my large tank so that it could also grow life and additional bacteria needed to cycle my large tank when I set it up, in addition to the sand. This tank seems to grow Ulva pretty well. I have a small hang on back power filter and a bubble sponge filter in the tank, and two garage clamp on light fixtures overhead with LED bulbs. Cheap and simple, but it works. Over the weekend, my daughter and I went collecting again and found some inhabitants for this tank. We added 6 adult blennies, 2 jumbo skilletfish, 5 adult naked gobies, and two mummichogs to the tank. We had one jumbo skilletfish, a live barnacle, a bunch of grass shrimp, and 3 mud crabs in the tank prior to adding these. When rearranging the tank and moving the oyster shells around, I discovered that bloodworms were living in the tank. Awesome! A natural food supply! I also discovered a tunicate that is alive and well, and is growing much faster than I thought that they would. I think that the Ulva is really responding to the heavy bioload. I have a little bit of cyano in the tank and some hair algae, but the macros (Ulva and a red algae) are doing well. The fish have only been in the tank for a few days and are already feeding out of my daughter's hand. All of the fish were eating mysis shrimp the night that we introduced them to the tank. All are fat and healthy.

Here's a video of the blennies in the 20g high (sorry about the music, I figured it was better than hearing our clothes dryer running):
https://youtu.be/hn8xIsLFZ_8

The water parameters of both tanks are great. No ammonia, no nitrites and very little nitrate, so the bacteria and algae are doing their job.

I really like the way you have balanced this system. I love the biotheme. I especially like you collecting crittes with your daughter. To a kid, love is spelled "time" together.
Kudoes to you.

 

[Chasmodes]

Awesome vidio! The translucent grass shrimp rock. They are very brave to swim in the open like that. Did you blue to oyster structure together. I like it. My first marine aquarium was a Galveston Bay biotheme. I gathered a large oyster cluster that took up 1/3 of a 55G tank. No live oysters, but numerous barnecles that would sweep the water with their 1/2 fans. That was in 1971 and I have been addicted every since.

Thank you Subsea!

So many blennies to choose from in Galveston! :bounce3: That must have been an awesome tank.

Yeah, I got the most of the shells from restaurants and also shucked some that I got from the grocery story. Then, I matched them up and glued each halve together with Gorilla Glue. After that, I glued them one at a time, fitting each one into a cultch. In this tank, you're looking at the largest cultch. There are about 8 cultches that will all form my oyster reef in my 101 gallon tank eventually. I put them in these tanks so I could start collecting, and at the same time, get some bacteria cultured on the cultches and also the sand in both tanks. Kind of like a head start. I have one barnacle, LOL, that I didn't know was there until I rearranged everything. There is also one sea squire. I hope both survive, but they may not since these tanks are relatively newly set up (less than 3 months).

As far as the grass shrimp go, I put a bunch in both tanks. Only a couple have jumped out, and most have lived. In my other tank, the fish ganged up and killed the largest one and at it, then did the same thing to one more. I don't think any have been killed since in that tank, and in the 20g high, I don't think any have been eaten. But, I'm not around all of the time, so it is possible.

That's the one good thing, there are plenty of shrimp to catch and add to the tank to replace the ones that get eaten. They've lasted a lot longer than I ever thought that they would.

 

[Chasmodes]

The naked gobies are exhibiting more color than I thought that they ever would. Some of their fins are trimmed with yellow or red (depending on how the light hits them) and also they get dark and the lighter areas between their color bands get bold white dorsally. Also, in these videos, it's easy to see the difference between the male and female blennies. The males have a blue spot on the front of their dorsal fin.

I figured out a way to get the fish to almost figure out that I'm not there. I need to build a canopy for my lights. For now, the cardboard box that my glass tank top came in fits perfectly as a temporary solution, placed there when I view the fish and removed when I'm done. I'll try and get a non-feeding video today and post it here. The fish tend to settle down and do their thing after feeding time is over, somewhat. They forage, get into territorial disputes, asserting dominance and challenging the pecking order, moving from one oyster shell refuge to another, chasing opponents...and looking for me.

But for now, here's another feeding video. Hope y'all aren't sick of my thread. I figure that this thread helps document my progress to my larger goal, the 100g tank once set up. I'm kind of learning as I go as these tanks are really a big experiment This video is amusing because the fish steal the food away from my daughter twice:

https://youtu.be/Iz9iLiCqUNE

 

[Chasmodes]

Not so good update of the 20g high... The tunicate and barnacle died. I'm bummed, but I expected that to happen. The fish are doing well for the most part. The largest killie still shows a spot on its side, but other than that, seems healthy and eating well, with no sign of distress. Both killies looked great until last night when I noticed that them and a few gobies had beat up tails. I watched them for about an hour after feeding to see who the culprit was, but still don't know. They all pick on each other a bit... blennies chase blennies, gobies chase gobies, killies chase killies, skilletfish chase anyone away from their hiding spot, and they all chase each other a little bit. But, none of them seem to do much damage. Well, except for the smallest blenny. I caught it biting a gobies tail, latching on hard and with a ripping motion. So, maybe I found the culprit. None of the fish go into hiding or seem stressed, so I hope everyone heals and moves about their daily routine.

The grass shrimp numbers are declining. Other than a couple carpet surfers, most of them probably were prey to the fish, although I didn't witness any predation. The crabs are a different story. I never see them, although I know that they are there, because they leave behind their molted shells. I'll have to check the tank at night to see what is going on. I still haven't done that.

I figured out a way to get them to behave naturally and not beg for food. Feed them. Duh...!!! But, that alone doesn't work because no matter how fat they are, they still beg for more. So, I set up my temporary "canopy" and also set up a DIY blind using shop clamps, a towel, a bungee cord and a hanger. After a couple minutes, they forget that I'm there. In the video linked below, you can see them acting more naturally. That is, until one of them spotted me moving at the end. Also, in the video, I came to realize that my killies might be a pair. Maybe some spawning activity? Hope y'all like it: https://www.youtube.com/watch?v=mTOJrQa9uRM

 

[Subsea]

Your tank rocks. For viewing at night, I use red LED, the critters can't see it. I have a separate blue LED for viewing phyoto luminance. Corals take in blue light as a high energy input and reflect back green as a lower light energy.

 

[Michael Hoaster]

You're getting a bunch of good videos done!

I would have thought the tunicate and barnacle would have had plenty of food, I'm guessing DOC. Maybe they need phytoplankton as well. I add phyto every few days and sodium silicate every other day for my sponges and tunicates.

 

[Chasmodes]

Thank you Michael. I think that I'll wait to stock tunicates and barnacles until the 100 gallon is established. But, I think that you're correct. There was enough food in there.

Update: In my 20g high, the largest blenny, that I thought was a female, revealed the blue spot on his dorsal fin, finally. The spot is hidden with a dark border, but when the light hits it right, it glows. That fish doesn't flare his dorsal fin much, at least until recently. He's king of the tank. The next largest blenny doesn't seem to have a spot, so I think that one is a female. The second biggest one doesn't really flare the dorsal too much, so it is hard to tell if a spot is there. The base coloration is totally different than the larger one. Although, there is a bunch of variation between all of the individual specimens. There is another small female, and the rest are males as they display their bright blue spots all the time. None of the blennies have shown any spawning behavior yet. They're pigs. All they want to do is eat. That said, the largest blenny seems to finally hang around one particular oyster shell for long periods, defending it. But, often abandons it in search of food. He chases all fish away from that shell, but it's hard to tell if it is because he is defending the shell, or just showing them all that he is the boss.

As far as the Ulva in the tank goes, it's doing well. I feed these fish heavily, so there are plenty of nutrients in this tank. That might explain why the sea squirt and barnacle expired (too much ammonia?). I don't think it was for lack of food, at least this time. I also moved them so I could observe them, possibly upsetting their environmental needs. They were alive and well before I intervened. I performed a water change after testing the water. There was a trace amount of ammonia, some nitrates and 50 ppm or so of nitrates. Out of about 30 grass shrimp in this tank, only about 10 remain at most, maybe less. I think the missing ones have been eaten. A couple jumped out of the tank. The grass shrimp in this tank hide a lot in the Ulva and Gracilaria, for obvious reasons, so it's tough to get a count. In the 20g long, where there are subadults and juvenile fish, the grass shrimp are always out and about.

It's tough to tell what sex the fish are in the 20g long as those fish don't seem to have any spot on the dorsal, but they're still a big small, I think. Maybe they haven't developed that coloration yet? A friend of mine who is an expert on Chasmodes says that they develop the spot early in life. If that is true, then my 20g long most likely the fish in that tank are all female. I performed a water change and cleaned out a bunch of cyano. Water parameters were zero for ammonia and nitrite, 30 ppm for nitrates. There are at least 8 grass shrimp out of about a dozen that I placed in there. I know of one jumper, the others may have been eaten.

The killifish seem to do a courtship wiggle or dance often. I don't know if they've deposited eggs or not. I haven't seen it happen nor have I seen any on the vegetation, although with the appetite of those fish, I doubt they'd last long enough for me to see them.

 

[Michael Hoaster]

Moving your barnacle and tunicate may have been the culprit. I know that sponges are very particular about their orientation to the current. Are you planning to keep live barnacles, oysters, mussels in the future? If so, do you know what their needs are?

You've got quite the fish soap opera going! Who needs store-bought fish!

 

[Chasmodes]

Well, yep, I have a lot of studying to do. It wasn't really in my plan, but now I'm interested in trying to keep filter feeders alive. I changed their flow and lighting, and I'm pretty sure that was the problem. I noticed that both closed up whenever fish were nearby. If the fish were nearby often enough, they'd never be open enough to feed effectively. That's my theory anyway. Also, the oyster shell that the barnacle was on became infested with hair algae to the point that it may have made it difficult for it to feed.

You've got quite the fish soap opera going! Who needs store-bought fish!

Yes, that's a great analogy! I learn something about their behavior each day. I had some doubts about keeping this many benthic species in a limited environment (even 100 gallons). But, what I've learned are the following:

- If the fish can handle the nutrient load of feeding them, then they seem to "get along" just fine. They do chase each other, even a little fin nipping. But, the picked on seem to heal up fast, and sometimes fight back. After they get chased, they don't hide in a corner of the tank or behind a filter, they go about as if nothing happened. This is true for all of the species in the tank.

- After my last collecting trip, all of the blennies and gobies came from one oyster box that is smaller than my 20 gallon tank. I'd say that they can get along just fine in a small tank environment based on that alone. I read so many posts about people worried about multiple blennies in a tank. I suspect that it depends on each species, but these are pretty aggressive carnivorous blennies, and with enough specimens to "spread the love", nobody gets picked on more than the others.

- Lots of hiding spots is the key, including good escape routes. These escape routes can be crevices in rock (in my case, between oysters in the cultch), through a mat of macroalgae, or within a hiding spot.

- Sometimes when a blenny gets chased, it simply spins does a lap around an oyster shell enough times that the fish doing the chasing either gives up or loses interest.

- Skilletfish are fearless. But, I'd say that all of them are not really afraid of each other.

- I was worried about mud crabs being a threat to the fish. After watching them around the fish, I no longer fear that as an issue. Blennies, gobies and skilletfish often land on them with no reaction from the crab, except sometimes they shoo the fish away with a claw, but do not try to pinch the fish.

- Grass shrimp live much longer in these tanks than I ever imagined. I thought that they'd be all eaten within a week. I'm pleased about that.

 

[Michael Hoaster]

Yes, I think it would be cool to at least give those filter feeders you can collect a try. They would be another great addition to your 'oddball' tank concept!

I do think your stocking levels may be a tad dense in your temporary tanks, but that shouldn't be a problem in the big one. Plus you're learning how densely you can get away with, and how to ameliorate any issues, with hidey holes etc.

How big do your crabs get? What do they eat? From what I've read about crabs in general, their biggest threat is at night, when fish settle down.

That's cool your shrimp are making it. In my experience, small shrimp added BEFORE the fish are safe (usually). Shrimp added AFTER the fish are food.

 

[Chasmodes]

Thank you Michael for your input, always appreciated.

Both species of these mud crabs get about 3/4" across tip to tip of the shell. That's about it. I think as the blennies grow to adulthood, the threat of being eaten is the other way around!

As far as the shrimp go, most of them were accidentally collected with the macros. The way that I look at it is, if they live as inhabitants, great. If they become food, great too, because I can get a bunch each time that I go collecting! :thumbsup:

So far, the tank is overpopulated and overfed, but the fish seem very happy and energetic and healthy. Also, I'm doing regular water changes and watching parameters, so I'm sure that helps. As far as inverts go, in the big tank, things should improve. It is just over 100 gallons and an additional 45 gallons if I plumb the sump in. Plus, the lighting is much better and should support all of the macro growth that I could ever want.

Oh yeah, forgot to mention. The white spot on the left side of the big (female) killifish was there for about two weeks. I didn't treat it at all since the fish wasn't distressed due to it aside from a little scratching now and then. Yesterday, I noticed that the spot has completely disappeared.

With regard to your comment on your thread about starting from the ground up with that tank...I most definitely will do that! Your advice makes perfect sense. Being fairly close to their natural habitat is a great advantage in that regard too. These tanks were a bit rushed to set them up, so I'm adapting as I go. Still, if these tanks succeed, then I'm confident the larger system will be that much better.

 

[Michael Hoaster]

I'm stoked! Can't wait for your masterpiece to be unveiled!

 

[Chasmodes]

Quick update:

Both tanks seem to have an increase in itching/scratching behavior. I don't see any visible parasites, but that doesn't mean they aren't there. It's hard to get a good look at them anyway because they move around so much. In fact, I'd say that there likely have been parasites in these tanks all along. All of the fish have scratched a little since the beginning. It's just more frequent now. So, what to do.

My assumption is that the culprit is Cryptocaryon irritans simply because freshwater ich doesn't seem to tolerate any salinity. From what I've read, C. irritans doesn't care for freshwater, so my initial plan is to reduce the salinity and perform a long term hyposalinity treatment.

Currently, the sg is 1.016. I plan to reduce it to about 1.009 and keep it that way for several weeks for each tank. I'd like to have these fish healthy by the time I get the big tank set up.

These fish are very hardy, so I don't anticipate any problems. The shrimp should be OK, as they are commonly caught at a lesser salinity than what I'm doing. My guess is that the mud crabs will be OK too, but I'm not 100% sure. I doubt the Ulva will make it through the process, but we will see.

 

[Michael Hoaster]

Hypo salinity sounds like a good call. You may also want to look at the Tank Transfer Method. Although, with my current knack for killing fish, I'm not a reliable resource in the fish disease arena. So, you may want to employ the 'costanza method', where you do the opposite of what I do…

 

[McPuff]

Hypo salinity sounds like a good call. You may also want to look at the Tank Transfer Method. Although, with my current knack for killing fish, I'm not a reliable resource in the fish disease arena. So, you may want to employ the 'costanza method', where you do the opposite of what I do"¦

I do agree that TTM is going to be your best bet. But then you have to be ready with a new display system and that is the rub. I don't see another way to ensure you rid your fish of ich for the long haul. I'm sure they did have parasites coming in, but in the wild it wouldn't have been too damaging for them. Obviously now, the parasites can get out of control for each fish. Argh, such a pain. That said, TTM is very easy and doesn't really require a lot of equipment/supplies, especially for smaller fish like you've got. Use a 5 gallon tank/container at largest.

 

[Chasmodes]

Thanks Michael and McPuff. I am going to try the hypo treatment first, simply because catching the fish and removing them to do the TTM might be very difficult, given the structure that they can hide in.

However, I've been thinking about how I might be able to pull off catching them and trying TTM, if I have to go that route. Since we've been hand feeding the fish in the 20g high and they're very tame, food and a net might be enough to catch most, if not all, of them. The fish are a lot more wary in the 20g long though, and those fish will be tough to catch, so hypo most likely is the way to go.

The good thing is that these fish face these types of salinity swings in the wild and are very hardy. Plus, I'd like the sand and oyster structures to be disease free. The change in sg isn't as bad as going from full sea water to a hypo state. I'd be reducing from 1.015 to 1.009 sg. From what I've read, that should do it. One of the problems reefers face when trying to use the hypo treatment is that inverts can't take the treatment, and lowering sg to 1.009 isn't possible, so eliminating parasites is very difficult. And, some fish can't take that type of treatment either.. I don't have corals or sensitive invertebrates to worry about.

Worse case scenario, if hypo doesn't work, I can fall back on the TTM.

Another thing, if I can pull this off, then I'll be confident that I can transfer the sand and oyster structures to my main tank disease and chemical free. And, I'd have an effective QT system in place for future collections. All I'd have to do is keep the QT hypo tanks running all the time, maybe with one hardy specimen (a killifish, for example) to keep the tank's biological filtration up to speed.

 

[Chasmodes]

Last night, I dropped the sg from 1.015 to 1.010. The fish behavior changed big time in many ways. First, all of the blennies and gobies went into hiding, including one blenny that spent the night against the glass at the filter intake. All of the other blennies hid in oyster shells. The skilletfish either hid or stuck to the glass, not much different than before. The killifish pretty much behaved the same and even kept feeding.

I think that it had an immediate effect on the parasites, maybe not killing them, but agitating them because all of the fish scratched even more than before (and that was a lot of scratching before).

This morning, nothing changed, all of the fish still hiding and the killies doing the same thing. I was a bit concerned about dropping it too fast that I might have hurt the fish. So, this morning, I tried to feed them thinking that if they perked up and ate, all should be OK, and if not...not sure what I'd do.

So, I fed them a block of frozen mysid shrimp. All of the fish perked up and ate, and many of them took the food right from my hand. They foraged a bit and then they went back to hiding.

The grass shrimp seem unaffected.

So, I'll continue at this sg for a week and I might drop it one more point if all goes well.

 

[Michael Hoaster]

It sounds like you may have shocked them a bit, with the rapid drop in SG. Luckily, going down is much easier on them than going up. Lower salinity actually makes it easier for them to osmoregulate. Bringing them back up should be done much slower for safety. Good luck!

 

[Chasmodes]

It sounds like you may have shocked them a bit, with the rapid drop in SG. Luckily, going down is much easier on them than going up. Lower salinity actually makes it easier for them to osmoregulate. Bringing them back up should be done much slower for safety. Good luck!

Yeah, that's probably what happened. I did it over the course of 4 hours per the instructions of what I read, but looking back, should have done it a little slower. I stopped at 1.010. I went back and re-read the article, and it says to go as low as 1.008. I may do that, but over the course of a few days after a week of them getting used to this level.

You're right, bringing it back up should be over the course of several days. I was so happy to see them come up and eat though!