Questions on Amphipods and Copepods

[Blazingreef123]

So I recently (yesterday) purchased a Mandarin Dragonette after having my 75g set up and running successfully for about 7-8 months now. This tank has a 29 gallon sump/refugium that is stocked with Fiji mud, live rock, and cheato algae. When I first set this tank up and let the cycling process finish I added some copepods and amphipods to the tank. I actually added both the Tisbe Bimeniensis and tisbe californicus strains of copepods to the tank. Over the course of the 7-8 months I have watched the populations of my amphipods and copepods steadily increase. However, something I have noticed is I don't see nearly as many copepods as I do amphipods anymore. The amphipods are everywhere, I constantly see them in my filter socks and anytime I move my rock around from the refugium to the display tank. So my question is, do amphipods prey upon copepods? I still find copepods fairly readily but nowhere near the amount of amphipods that I regularly see. Now this could be because of the obvious size difference and how I perceive the difference in population, but it used to be I could look into my refugium and see a good 4-5 copepods in a square inch, now I'm lucky to see 1 every square inch. If any experts could help me out on this I would greatly appreciate it! Also, if there are any successful or experienced Mandarin Dragonette keepers here please chime in on any useful information you may have for me! He is currently in quarantine in a 40g breeder and I am simply mesmerized by this guy! I absolutely refuse to lose him!

 

[Entacmaea]

In our small tanks, it is common for one pod to out compete another and you end up with a less diverse mono-culture - but you should still have both copepods (smaller) and larger amphipods. Usually amphipods in our tanks feed on micro/macro algae and detritus, but that is not to say some not opportunistic feeders, but I doubt they are predatory to an appreciable degree. If you keep your glass clean, you might not see the smaller copepods as much - at least on my tanks I would rarely spot them on the rock, just on the glass feeding on algae film, and on the darker contrasting cheato in the fuge.

While you have your Mandarin in QT - get him trained on pellet immediately, and before you move him to the DT. Your 75 gallon is small to support one Mandarin long-term without supplemental pod additions or feeding, so best to train him while isolated. There are some good resources out there for DIY Mandarin Feeders - basically small plastic tubes or long boxes you put small pellet in, and they eventually learn to go in and get the food. This is MUCH better achieved while in QT without competition from other fish. Mandys are so shy, training them in the DT can be tough. Stay away from training them on brine, as they are not nutritious enough without enrichment, which takes dedication.

One thing I tried with good success was adding a breeding colony of peppermint shrimp - 8-10 in the fuge or other isolated section. Feed them well, and you'll get the females to lay a steady stream of eggs (you can actually see the green eggs under their abdomen). I would regularly see tiny peppermint shrimp in my tank, likely food for everyone, and I hoped for my Mandy as well. Try to get aquaculture peppermints if you can - ORA breeds them.

Also, make sure not to keep any competing pod eaters - no Wrasse, psuedochromis, etc.

Hope that helps!

 

[Entacmaea]

PS - Welcome to RC!

 

[Blazingreef123]

Ahh the peppermint shrimp is a great idea! I will definitely have to get some and put them in my fuge!

So as far as the wrasse comment goes, I actually avoided getting any type of wrasse for that exact reason. My tank consists of 2 clowns, 2 yellow-tail damsels, a firefish, red skunk cleaner shrimp, and a yellow watchman goby, and hopefully soon a mandarin dragonette.

I have actually been trying one of those DIY methods I saw with a pasta sauce jar and pellets in the bottom of it like a buffet and today my brine shrimp will be done hatching and I'm going to cover the pellets in them similar to the food ratio method and try and get him to "accidentally" eat a pellet which I'm fairly sure he has actually already done at least once. So I'm really hoping for the best!

However this morning I'm running into some troubles with him. When I set up his quarantine day before yesterday I decided to not risk any chance of ammonia or nitrite issues so I placed 2 large pieces of LR from my display tank and fuge into the 40g breeder QT with a handful of live sand and I have been transferring about 15g at a time from my main tanks water into the QT. then giving the DT new water. This worked great day before yesterday I started him off in QT in about 20g of the water from my DT and this morning I transferred over another 15g to have him in a total of 35g now. about 10 minutes after transferring that water he is now pacing back and forth at the top of the tank, and has been doing so for the last 15 minutes.

Now here is the part that is really throwing me off. I cant imagine it is oxygen levels, because I have an airstone and a powerhead in there pointed at the surface. So I decided to check ammonia and nitrite levels just to play it safe, well the API test read .25 for ammonia. Which seemed strange to me since I have the LR in there. So I decided to test my main tank with it. It also read .25 which as of 2 days ago DID NOT read .25 it was at 0. So I cant figure out why I would have had an ammonia spike (small) in my main tank and QT tank... But I'm not sure. Any ideas here?

Thanks for the quick reply! :thumbsup:

 

[Entacmaea]

Hey there - I'd first check your test kit on some RODI water, to make sure it is correct. An ammonia spike on an already cycled tank can mean a few things - either something large died in the tank, or something has affected the biological filter (bacteria die-off) so they can not process waste. I'd do water changes immediately to get the ammonia down, if that is in fact the case. It is also possible that you removed enough LR from the main tank to impact its ability to process the bioload, ammonia increased as a result, and that ammonia laden water was transferred into the QT - hence the similar levels in both tanks. That is just speculation though...

 

[Blazingreef123]

Well as it turns out, I think I may have found a possible reason for the ammonia spike at least in my DT. it turns out that after feeding my phytoplankton to the fuge (in which I shut my return pump off) I accidentally left the pump off all night Which would have taken at least 10-15% of my LR out of the question for that system. Then I realized that I had taken that same water before realizing this and put it into my QT. :headwallblue: I'm going to have to run to the store and fill my 5g jugs full of RODI water because I just ran out for water changes and my RO system will take at least half the day to give me the 40g I need for a water change in my DT and my QT. :headwalls:

By the way, shortly after posting about the mandarin doing that at the top of the tank I went ahead and started doing a process of elimination, I shut off the powerhead and within 10 seconds he swam back to the bottom and calmed down. So I decided to put some brine shrimp and pellets into his jar and he started picking a bit at the entrance to the jar, as of this second my phone is leaned up against the tank (in the other room so he can't see me) and recording his actions so I can let him eat peacefully with out disturbance. I'm hoping this will give me a good idea of his eating habits.

 

[hotelbravo]

i had a mandarin in a 90 gallon for over a year. i had my mandarin eating pellets and mysis but he still starved. the tank had a 30 gallon sump and was packed with rubble and tons of caulerpa and other macro algae. i had spent about $200 on copepods over about 5 months before i ever added the mandarin. all of this preparation was not enough to keep the mandarin alive even though it did live for a year and a half it started to get skinnier and skinnier as the months past. there were always pods on the glass and amphipods on the glass but that was still not enough.

i wish you luck i really do. many have done it successfully in smaller thanks or the same size tanks but they are few and far between.

since april i have been adding pods to my 180 gallon and i plan to get a mandarin in december but im still nervous.

 

[Entacmaea]

careful - assuming your heater is in the sump(?) your tank temp could have dipped with no circulation over night and significantly impacted bio filtration in the main tank to a large degree, i.e. killed lots of bacteria, or killed off lots of micro fauna - hence the ammonia spike...

 

[Blazingreef123]

Actually I don't have a heater in my tank. I take them out during summer months and just let the AC do the work. The temperature in my house stays between 72-76 consistently. I haven't noticed any impact on my saltwater tank or my 2 freshwater planted tanks, however that's not to say its not making one.

 

[Blazingreef123]

i had a mandarin in a 90 gallon for over a year. i had my mandarin eating pellets and mysis but he still starved. the tank had a 30 gallon sump and was packed with rubble and tons of caulerpa and other macro algae. i had spent about $200 on copepods over about 5 months before i ever added the mandarin. all of this preparation was not enough to keep the mandarin alive even though it did live for a year and a half it started to get skinnier and skinnier as the months past. there were always pods on the glass and amphipods on the glass but that was still not enough.

i wish you luck i really do. many have done it successfully in smaller thanks or the same size tanks but they are few and far between.

since april i have been adding pods to my 180 gallon and i plan to get a mandarin in december but im still nervous.

Hotelbravo, when you had your mandarin did you try the glass jar buffet method? Where you literally take a glass jar, put it in the bottom of your tank in a corner and then fill it with pellets and mysis shrimp? This keeps virtually all competition away form the mandarin and they are free to come and go as they please and whats great is not a lot of water flow reaches in the jar so the ammonia that would be created from the decaying food can be removed if you don't allow water flow when removing the jar. I remove it and clean it and refill it daily.

 

[Blazingreef123]

To my knowledge mandarin dragonets do not actually have a stomach, therefore they lack the means to store food that say you fed in the morning. They absorb the nutrients they need at that moment then expel the rest. Hence why they constantly feed on copepods even after being fed pellets, mysis shrimp, etc. So if you leave this buffet they can constantly eat as they please.

 

[Entacmaea]

Yeah - you definitely need a heater - 72 is subtropical and too low, and a 4 degree temp swing is way to much for long term health of much, especially corals...

I'm not sure about the no stomach thing : ) Haven't heard of an organism in Actinopterygii (bony fish) that don't have a digestive tract. They forage all day since their food is small and they need lots of it, much like tangs graze all day on algae in the wild. The processing efficiency of their system I can't speak to, but I'm pretty sure they have a digestive system like other fish.

 

[Blazingreef123]

Heaters are definitely going back in then! Out of curiosity what is your preferred temperature for reef tanks? I try and keep all my tanks at exactly 76 F but I would love to hear your opinion.

As far as the no stomach thing goes, I remember reading it on a zoology website but I can't remember if it was someones comment or actual content of the article. believe me I would be MORE than happy to be wrong, and logically I probably am :lolspin:

 

[Entacmaea]

Hey there - there are lots of opinions on temperature, I would say probably 78-80 is the most common range. I think there is an RC poll somewhere about it. I keep mine at 78. Stability (no large daily swings) is more important than a specific temperature, but a tank temp around 78 is probably good to shoot for, and will be most acceptable to the widest range or organisms. A daily temp swing of .5-1 degree is probably not a big deal, but keep in mind that ocean temps are usually very stable. They do have seasonal temperature swings in nature (rising/lowering several degrees over the course of many months, but that is something that we probably don't need to, or shouldn't, try to emulate in our tanks - stability is more important.