Gutted, just lost a whole brood in hours

[kev1310]

As the title says, I'm gutted, for the first time in 6 months I managed to get a batch of pigeon blood babies to attach to their parents a couple of weeks ago. Since then everything was going well. No losses, all 200+ young were growing well and as of yesterday had been free swimming 12 days and had been eating BBS for a week, that is all going well until yesterday

Yesterday morning all was well, they were fed first thing and again at 10am. Yesterday lunch all looked well, went out at maybe half two and noticed the young looking listless and lethargic and a couple were swirling. Knowing I'd squeezed the sponges out the night before and done a 25% water change I immediately suspected ammonia or nitirite, but:

TDS 130
PH7.7 (normal)
Ammonia 0
Nitrite 0
Temp 85
I don't test nitrate


I immediately removed a bunch of them to a breeder net in another aquarium and did a 50% water change on the parents tank as a precaution. Things only got worse....

By 4pm all of the fry were looking ill and not trying to feed from the parents and some had started to die. By midnight all 200+ were dead, both in the main tank and the breeder net I had two initial thoughts, a spike in water quality however tests yesterday afternoon and again last night came back normal.

My second thought was some form of problem with the BBS I fed at lunch, however the same BBS were fed to two batches of cory fry and another batch of baby discus that were artifically raised and 5 days older - there's been no issue with any of them at all. The ONLY thing I can imagine is that I fed too much and something happened. I did give them a larger than normal feed at about noon and all bellies were very full when I checked them about 2pm.

I'm a bit lost as to what went wrong to be honest. They went downhill so quickly it was unbelievable. Ammonia and nitrite test kits are both about 3 months old. The parents are obviously looking a little lost. They are brilliant parents, I don't suspect them at all, none of the babies had been bitten.

Anyone else had anything like this happen before?

[danotaylor]

Kev I am really bummed out to hear about your losses mate, that really sucks bad
It does seem like a water quality issue related to bigger than normal feeding after squeezing your sponges, but I wonder if you have treated the parent for gill flukes? I think flukes typically kill fry at or around the 30 day mark, but it's the only other hypothesis (other than water quality) that I can think of that would have such a catastrophic effect on the entire batch.

[kev1310]

Hi Daniel,

thanks, yes, the parents were clean and had been treated for flukes a couple of weeks earlier. Up until last year I'd regularly had trouble losing fry to flukes and it always happened over a matter of weeks, this was much, much faster, literally the young all looked absolutely fine at lunch and by midnight I'd lost them all.

I can only assume it was some sort of water quality issue or overfeeding. The sponges were squeezed out in tank water though and all water going through the fish room is either RO treated or HMA treated and filters were changed only two months ago, plus, the other fry tank seems unaffected, and a 50% water change didn't improve things and the ones I moved to the fry net in a different tank went downhill just the same. I'm just completely baffled by it. I've not done anything different to what I normally do and I've never lost a brood like this.

[danotaylor]

Mate that really stinks...sorry I couldn't be of more help...I hope you get an answer though so this doesn't happen again. All the best as you recoup bud

[dspeers]

Is there any possibility that the 25% water change contained chlorine/chloramine. Chlorine toxicity fits the bill of rapid but not immediately lethal, more toxic to fry than adults and the scenario of 100% fry dead within several hours suggesting exogenous toxin rather than infectious cause.

.006 mg/L will kill fish fry in about two days.
.003 mg/L will kill insect larvae, such as dragonflies.
.002 mg/L will fatally damage the sensitive skin on tadpoles, frogs, salamanders and other amphibians.
.01 mg/L is the maximum level that experts say adult fish can tolerate.
.25 mg/L is the level at which only the hardiest koi or other pond fish can survive.
.37 mg/L is the level at which all pond fish will die.

[kev1310]

Nope, zero possibility Don. For a start our water company states on it's website it doesn't use Chloramine, plus all make up water has gone through either an RO unit or a HMA filter, both had filters changed a couple of months ago, plus, it's heated and aerated for 24 hours before use.

Given that the water change was done 12 hours before symptoms showed I'm inclined to think it's not the make up water, plus, my other brood just 5 days older is completely unaffected.

[dspeers]

If you had not used on other fry I would suggest you test to confirm that new filters are also fully functional filters, but if you used on the other brood, no point. What a puzzle, epidemiologically this looks like a point source toxin, meaning all of the fry were hit at the same time with a one time lethal dose of something. Neither the water nor the food affected other fry so both are basically ruled out, but what that something is I have no idea, good luck.

[kev1310]

Yeah I'm stumped Don, never before have I lost a brood of any fish like this. Even given that I did a 50% water change straight away and moved some to another tank neither made any difference whatsoever. The parents seem completely unaffected. I've found just one survivor which has now been placed in with my slightly older brood and is eating, although with it being so much smaller I don't know how it will do.

Like you say, it does sound like a toxin of some sort, especially to act so quickly, but I'm stumped as to what it could have been.

[fljones3]

Sorry for this, Don. I cannot imagine (especially without a ready knowledge of what caused it).

[CliffsDiscus]

Sorry for your lost. The sounds like Velvet cause by high density, overfeeding and low percentage of waterchanges.

Cliff

[kev1310]

Thanks Cliff, I was hoping someone with more experience might have some sort of explanation.

I'll make sure I up the water changes next time, plus I think once they're onto brine shrimp I'll separate a few as an insurance policy!

[LizStreithorst]

Thank from me too, Cliff. I've followed the thread but wasn't able to figure out what might have gone wrong. Kev, they'll spawn again so there will be a next time soon.

[CliffsDiscus]

Liz thanks,
I only know because it happen to me more than once.

Cliff

[pastry]

Kev,
Great thread. I know it sucks and sorry that happened, but you sharing that with us is top notch in my book. Especially with Cliff responding because that's not my lane by any means, but I still want to breed in a better, controlled environment eventually and this is a thread that helps. Best of luck, brother!

[LizStreithorst]

It happened to me once upon a time, but it was too long ago for it to click in my head. Since then, I've had disasters from other causes that are closeer to the front of my memory.