BABY FISH, but what are they?! HELP!

[mwp]

Around 9:00 PM this evening I was feeding adult and nauplii live brine to our cardinal tank when I noticed some "withing" wormline creatures at the surface. Upon closer inspection, they're BABIES! But wait a second...

They're NOT cardinalfish!?

I'm ruling out the cardinalfish for now...here's why:

1. They're obviously NOT "Bangers"...

2. The Apogon leptacanthus have not noticeably bred nor have either of the suspect males gone on a "hunger strike". I beyond highly doubt they are the parents.

3. The Apogon margaritophorus. Well...HMM. Here's the deal since my last posting of "fish porn". It "looked" to be that the males ATE all the eggs immediately. None of the cardinalfish have gone on a hunger strike. The female, in her botched spawning, has appeard to have her ovipositor extended since then, leading me to believe that she had possibly gone through a bout of egg binding and perhaps was not going to be a viable spawner anymore (suffering internal damage when trying to pass the eggs and failing). However, as I write this, I have to make the following disclaimer and I KNOW I'm gonna sound nuts.

PERHAPS the "ovipositor" was NOT an ovipositor, because now it's GONE. The orange stuff hanging at her abdomen *could* have been eggs - as of writing this now (12:00 AM) the "ovipositor" is "gone" and the female looks SKINNY. LIVE BIRTH? Medeka Fish style brooding? I know, like I said, NUTS.

So if they're not cardinalfish, what are they?

1. Our pair of Green Mandarins...hmm. Well, the female has been in "isolation" (a net breeder) for the past 3 days in an attempt to fatten her up and get her eating frozen foods (it WORKED too this afternoon!). Not likely in my book.

2. Our "possible pair" of Firefish? I must say, the "suspected" male has been out and about more in the last 48 hours...perhaps they had a successful spawn?

3. Our Greenbanded Gobies who formerly hated each other until my last post where I caught what most of you agreed was courtship behavior. These are tank-raised fish. They have been mostly in hiding the past few weeks. Kinda leaning towards these guys myself.

About the larvae

1. Sorry, no metric ruler around, but they're around 1/8" in length.

2. The Brine nauplii I have on hand was hatched 2 evenings ago...it's definitely TOO LARGE for them to eat, but they really, really want to.

3. L Strain rotifers seem like they could be the right size, but I haven't noticed any feeding.

4. The larvae are positively phototrophic.

5. They kinda move like gobies in a jumpy, herky jerky fashion, but at times they make mad dashes, moving rapidly through the water just under the surface.

6. They're transparent with "3 spots". The first "spot" is the eyes. The 2nd spot appears to be the gut. The 3rd spot, before the tail???

7. The larvae appeared around 9:00 PM this evening, typically 1-3 hours before "lights out". Hatching lasted maybe 1 hour. As of lights out (11:00 PM) no new larvae have been found.

8. When "appearing" they'd make a mad dash for the surface, popping out of the rockwork almost like corks held underneath water. At times 5-6 would "pop up" together.

9. Brood size - well, I didn't find any in the mechanical chamber of the nanocube and today it's not "surface skimming" anyways. I collected approximately 50 babies.

PICTURE

Video

Quicktime Format, around 2.8 mb, 10 seconds.
http://www.cichlidrecipe.com/nanoreef/DSCN0607_1-22-06_larvae.MOV

What next?

Well, I feel the larvae are too small to place in a "breeder net". I don't have any free tankspace on hand either, so I have the larvae roughly split 50/50 into two specimen cups (one large, one small).

Into the small one I placed the 2 day old brine nauplii until I realized these fry are WAY too small to eat them. I also placed L-Strain Rotifers and 10 drops of phytoplex.

The large specimen cup contains L-Strain rotifers and just a couple nauplii I didn't get out.

My plea for help!

1. I don't have any live phytoplankton cultures going, and I fear I may need them! I have Kent's Phytoplex, Reed Maricultures "PhytoFeast Live", and Liquid Life's phytoplankton on hand. Will any of these work as a substitute, and if so, which one is better? Conversely, if anyone in the Chicago area has extra live cultures, I'd love to talk!

2. Rotifers - right now I've been sifting these through a coffee filter (I have a 53 micro sieve on order but it's not here yet!). Anyone have any help for me in this dept? I can't say I've seen these guys eating any of the rotifers yet....

3. Just a general help plea for anyone's assistance - considering these are unknown babies I REALLY, REALLY want to raise them to find out what exactly we got, unless someone here can make a 100% firm ID with the info, pics and vid at hand!

Thanks and wish us TONS of luck...while I have tons of experience with the African Cichlids, larvae this small, let alone MARINE...we'll, they're new to me! I'd simply be happy with getting them large enough to figure out what they are - everything we're keeping in this tank should, in theory, be "rearable"!

MP

 

[NicoleC]

Well, they look a lot like my gobies. I don't suppose that helps much!

 

[ediaz]

From the video and the description of the hatch those are GBG.

The rotifers will be ok, the tank is to brigh/shiny that will prevent them from eating. There is a few breeders there, you should be able to get some phyto.

The algae substitutes should work for now, you will have better chances with it than without it. In a emergency you can use powdered spirulina from a health store, mix with water and add to the larval tank.



The good news:
It will happen again

Get a black plastic tub for the next hatch

Ed

 

[mwp]

Ed, thanks, that's the kind of info I was hoping for. A black plastic tub 'eh? I think I might be able to jerry-rig something in the meantime. HMMM.

Well, guess those GBG are a pair afterall!

MP

 

[clownfish75]

Look heaps like my banded goby larvae too.

Christian

 

[mwp]

OK, so we killed off one half of the batch already, not even 24 hours in!

HELP!

On the upside, we found another dozen babies in the tank this evening.

So here's how we're set up.

Large Specimen Cup - roughly maybe 25-30 larvae captured last night. I've introduced a "fair amount" of L-Strain Rotifers last night. Added 10 drops of phytoplex this AM, along with a cup's worth of rotifers that were enriched with 2 drops Selcon overnight. Added more rotifers this evening. Admittedly, it looks like some larvae are going downhill. I added an air-feed this evening, bubbling around 2-3 bubbles per second. I also removed 1/4 of the water this evening and replaced it with tank water.

Small Specimen Cup - this also had maybe 25 larvae last night. It inadvertently got a thousand or so 2 day old brine shrimp nauplii, + rotifers, + 10 drops of phytoplex last night. This mornign I gave them another 10 drops of phytoplex and a baster full of copepod nauplii (from the "Tiggerpods" that Reed is putting out). This afternoon Renee came home to find all the fish dead. She simply poured it back into the tank, filled it back up, and placed the dozen or so new larvae into it.

So here are my questions and comments - obviously I'm not set up for GOBY breeding; was more ready for the Cardinalfish since those were the primary focus!

1. Why would the lighting be too bright for them to feed? From my readings, the issue with painting the sides of the larval container black and only lighting above is to make sure no light enters from the sides so they larvae orient themselves correctly for feeding. In our setup, I have each specimen cup hanging at the front of a 24 gallon Nanocube, the lights are not "directly" overhead, more like 45 degress off from straight vertical. MOST all of the larvae collect along the far edge at the waterline, orienting to this light source. The room is otherwise dark, blinds closed, so no outside light gets in anyway. If I really need to fix this and "black out" the sides of the cups, the only thing I can think of offhand is that I have black plastic bags that come from the corner store. I could rubber band them around the cups, assuming they're not toxic to our tanks?!??!

2. Phytoplankton - why is this necessary in Goby culture? From what I've been able to read, the Phytoplankton is not eaten by the larvae. The best I can come up with is that it's simply used to keep the rotifers alive, basically making our larval rearing containers a rotifer culture WITH FISH BABIES? Regardless, how green does the water need to stay with the fish larvae in there? I haven't taken it past "slightly cloudy" yet, but already killed off half this batch somehow (and suspect it was the 2nd 10 drops of Phytoplex).

3. Rotifer density - since I cannot visually observe our rotifers under a microscope or magnification yet, how can I best estimate if the rotifers in the tank are "thick enough"? It seems like I can see adults, and a VERY, VERY FINE powder in the water that might be "juvenile" rotifers for lack of a better term (keep in mind I do have 20/20 + vision). My eyes are my only gauge at the moment...

So tell me what I'm doing right, what I'm doing wrong, and any tips to make my shoddy setup work to raise even a couple is good enough for me for now! If there's something else I can add that may help, let me know!

New tanks for the moment are out fo the question, and so far I haven't located any local phyto cultures in Chicago + the setup time to get these going won't help this first batch.

Thanks to all of you for the likely ID's as to these larvae being GBGs - that means they're hope for me yet! If they're firefish...well, we'll really be up the creek!

Matt

 

[NicoleC]

IMO, it's too soon for them to have died from lack of food. They only hatched last night right? Must be something else. How small were the "specimen cups?" Small enough to make a tiny little water parameter change into a giant problem?

A green tint to to the water helps most larvae feed. Just a tint, though, if you aren't using live phyto. Otherwise to much it can foul the water very quickly and can wreck havoc with your pH within seconds.

Take it easy for a bit. It's a steep learning curve. Your pair may not be producing healthy larvae yet, or ones large enough to take L-strain. My first attempts to raise YWG on L-strain got nowhere fast, then suddenly they could take it. Did they increase in size, or did I get better at it? Dunno.

Also, in that pic I see no yolk sac. So I take back what I said about starving in less than a day. Maybe Edgar can say if that is normal for them, or if perhaps your pair is undernourished or just not up to speed yet.

 

[mwp]

<a href=showthread.php?s=&postid=6570783#post6570783 target=_blank>Originally posted</a> by NicoleC IMO, it's too soon for them to have died from lack of food. They only hatched last night right? Must be something else. How small were the "specimen cups?" Small enough to make a tiny little water parameter change into a giant problem?

The smaller specimen cup is roughly 0.24 gallons, the larger is 0.59 gallons.

A green tint to to the water helps most larvae feed. Just a tint, though, if you aren't using live phyto. Otherwise to much it can foul the water very quickly and can wreck havoc with your pH within seconds.

This is indeed possible, especially with the relatively "large" dose of phytoplankton (I typically give the rotifers 10-20 drops of Phytoplex, twice a day, in a 1 gallon culture, I have 3 cultures going right now). The additional dose of phytoplex this AM definitely could have been the culprit.

Take it easy for a bit. It's a steep learning curve. Your pair may not be producing healthy larvae yet, or ones large enough to take L-strain. My first attempts to raise YWG on L-strain got nowhere fast, then suddenly they could take it. Did they increase in size, or did I get better at it? Dunno.

Interesting comments, thanks! The one thing that has me "unable" to "take it easy" is the fact that while my guess and the guesses of more experienced breeders all point to the fry being Greenbanded Gobies, there's still a possibility that these are Firefish. I just "gotta" know, ya know?

Also, in that pic I see no yolk sac. So I take back what I said about starving in less than a day.

Indeed, unless that "gut" spot was in fact a yolk sack, these fry looked ready to feed with no reserves.

Maybe Edgar can say if that is normal for them, or if perhaps your pair is undernourished or just not up to speed yet.

Well, I can safely say that the breeding pair of whatever they are isn't undernourished as per the heavy feedings of enriched diets the tank gets every day. Productivity of eggs in my cardinalfish hasn't been an issue (granted, haven't gotten live fry yet). Anyway, I'm really, really confident that malnourishment of the breeding pair isn't an issue.

Inexperience and youth, those definitely could be factors.

So the lastest update

It indeed looks like these fry are starving. The ones in the larger specimen cup are losing vigor and starting to sink to the bottom, none dead yet but who knows. Overall, it seems that both the "day old" larvae and the ones we found this evening are not as strongly "positively phototrophic" as they were yesterday....

Looking forward to more good comments!

Matt

 

[ediaz]

The light is attracting them to the corner of the tank. This will prevent them from feeding is not light form the sides, any source will attract them.

They eat phyto, I had some analized before.

Any rotifer will do.

Those are healthy larvae in the vid, great vid , wish everybody had something like that when it's time to identify a fish or a problem.

Ed

 

[mwp]

Thanks ed for those comments. We lost MOST of the larvae in the large specimen cup overnight. We only lost one of the 'new larvae' that we found yesterday, which are currently residing in the smaller specimen cup. We have probably less than 20 total now.

Regarding the lighting issue, some of the "new fry" are now behaving more like "normal fish" swiming and possibly "hunting" at all levels within the specimen cup. I've observed what looks like feeding behavior...a larvae will stop, whip it's head back and forth like it's trying to tear something apart, and then continue on.

In most of the articles I've come across, they seem to state that light from the sides is the cause of troubles, disorienting the feeding larvae. It seems that some folks do run lights above their goby grow out systems, with the sides and bottom blacked out. How does a grow out system like that NOT attract all the larvae to the surface resulting in poor feeding?

I'm kinda leaning towards discontinuing use of the "off the shelf" phtyoplankton feeds following the amount of deaths we've had so far. I noticed that Phytoplex has citric acid in it...definitely not helpful in maintaining the proper pH! I think these guys will have to go with straight Rotifers for now...

Thanks for ALL the help and advice thus far. All I need to do this first time around is raise ONE long enough to find out, with 100% certainty, what species we are dealing with!

Matt

 

[mwp]

Well, we were down to 6 larvae, not looking to good, so as per the crazy idea running around in another thread with Olin, I figured "what the heck" - threw the last 6 into one of the rotifer cultures. I'm highly doubtful we'll see any positive results at this point! Well, 24 hours and they're dead, that seems to be the track record so far...

Hopefully some more will show up in a week or two!

MP

 

[olin]

Yeah, the rot culture is probably teeming with nasties- ammonia and vibrio. best to add fresh greenwater and filtered rots to the rearing tank then let the poly culture develop.

 

[mwp]

Well Olin, 24 hour survival rates this first time around just aren't gonna cut it. I've bit the bullet and ordered starter cultures of Nanochloropsus, Tetraselmis, and Isocrysis. For the last couple months my "live food" culture has take over....I swore I wouldn't expand it....

HA...then I realized I have room for about 10 or 20 2 liter bottles behind the ORCHID SEEDLINGS on my light-rack - PHYTOPLANKTON CULTURE STATION HERE I COME!

Just hoping that if I set this up right I won't have to worry about salt spray - Pahiopedilums and salt definitely DO NOT MIX

Matt

 

[olin]

Orchids AND larval rearing? Glutton for punishment! With only 24 hour survival, I might also look at more than just food. That is probably it, but even without food (I'm as forgetful as the next) I've had reasonable survival off yolk sacks for 36+ hours. Try putting a tablespoon of activated carbon in a clean nylon stocking and dropping that in the tank near the airstone. Several vibrio species secrete toxins that can cause mass mortalities. Carbon really helps. I've done some experiments with toxic supernatants from bacterial cultures and prevented mortality with carbon. Like I said, this is probably not the case, but something that can easily be ruled out. I know what you mean about the cultures- soon I won't have room for my fish!

 

[mwp]

Ah, Orchids are cake compared to raising fish. Water & fertilize every 5 days or so, repot once a year and more or less watch 'em grow

I WILL try the carbon next time. There's also the possibility that the issue was with trying to use such a small rearing container...while stable due to the fact that they're installed INSIDE the larger tank, water quality issues could definitely come into play. I've toyed with the idea of creating a very small "flow through" system with some tubing that would allow for slow turnover through these tiny rearing stations from the main tanks. Additional tanks are, at the moment, not an option!

MP

 

[NicoleC]

I tried using 53um mesh to create containers I could use to super-aerate the tank. It didn't work. The gas exchange was poor, and the mesh quickly became clogged.

I suspect you will have the same issues with a flow-through system -- any smaller mesh and you won't keep the rotifers in, and you won't be able to remove and clean it.

 

[mwp]

So the verdict, at least my verdict, is that we didn't get them enough suitable foods. If you haven't caught my "Copepods in the Rotifers" thread, to summarize, looks like my rotifer cultures were heavy on copepods (2-4X the size, 10X the mass of a typical L-strain rot) and very light on the rotifers. I only know this now having observed some samples under 10X magnification.

Started up Tetraselmis, Nannochloris and Isocrysis as well as some "clean" rotifers...was hoping we might find another hatch maybe tonight, but not yet. All in good time!

MP