Mass die-off of fry

[Barb]

I have bred BN plecos before, had no problems. I just had a spawn of longfin calico BN plecos. It has been 3-4 weeks roughly and all of a sudden I am having mass die-offs of the fry. Not sure why? They are in a 55 gallon, heavily filtered with two AC110's and a hydro sponge filter. This tank has been running for a year at least. There are also guppies in the tank (around 20) with lots of guppy fry (no die offs with them). There is one male BN and 3 females. Two cories and that's it for livestock. I do weekly w/c of 50%, bare bottom tank, driftwood. There is always zucchini in the tank for them, flake food is fed twice daily, pellets also. Nitrates are around 10-20 so not too high.

Any idea as to why this is happening? Are they starving? I can't figure out what I'm doing wrong.:banghead: I'm doing the same procedures as I have done with the standard BN plecos I've raised before.

[Hitch]

I am assuming you tested the water and everything is good? have you seen them eating? If you have I doubt its starvation.

Maybe the 50% water change was too much of a shock (water chemistry and temp wise?) for them....not too sure.

[Zebrapl3co]

Frys are very sensitive to nitrate. Maybe you should lower the nitrate. If you are really overfilter, then you shouldn't see a 10 - 20 nitrate but a 0 nitrate. So, not sure what's wrong there. Apparently, you are not overfilter as you said. Maybe one of your filters aren't working or maybe it's time you clean then.
I never stuff my frys, baby frys can't control their eating. Some will die for overeating. So you might want to scale down on the food. Are you providing a good balance of vegies? BN maybe ominvours, but they need vegies in their diet.
High copper and lead is also detrimental to their health as well. If you fix the two I mentioned, and are still getting high rates of death. Then you might want to test your tap water for copper and lead.

[Barb]

I shall go and test for nitrates again. I clean the filters in tank water alternating filters.

Just tested and did a water change. Nitrates were 5 before the w/c. Not many left of the fry though. I'd say out of 40-50, there are 10 left.

Water is good, no copper or lead. I have a discus tank also so they are pretty sensitive to water issues and I do daily w/c on their tank. If it was something in the water, they'd be the "canary" to tell me.

I don't know what is going on. I was only feeding flake once a day, maybe go to twice daily?

[Bwhiskered]

This mass dying of bushynose fry is unfortunately not new to me. My problem is mainly with albinos. I can't help but think it has something to do with our lake water. My albino fry do just fine as long as they stay in the parents tanks. They can be crowded and water conditions even poor and they still do fine. Move them to a tank of their own and they start to die after a period of two or three weeks. I have checked water and tried changing their diet and tried medications with few results. I have gone from raising 2000 a year to only a few hundred. A breeder in Oshawa had this problem first and I got it a year later. Could be what the water treatment plants are doing or just something we can not put a finger on. Last week my tap water tested out at stress for ammonia nitrate. Still trying different things to try and solve the problem. I have found the problem less with brown or calico fry and no problems with other species. Just want you to know that you are not alone.

[Zebrapl3co]

That is really strange. If you suspect that it's the water, then using RO water would've solve that issue. Could it be that they are pH sensitive? Alternately, they could die as a result of TDS fluctuations.
Also, if you are doing OK and sudently start getting die offs, then it might be a bacterial issue. I did have that happened to me with one batch quite a few years back. Those are the spotted BN pleco. I blame that from a new fish I picked up from BA. I quarenteen the fish and it was OK, but I must have picked up some kind of weird bacteria as I started losing my batches. I treat my tanks when melafix for 4 weeks and problem went away.

[Barb]

Yes, it is puzzling. I have raised brown standards no problem, this first batch of calicos am having them die off. I thought it was not enough food. Water issues there is no problem with any of the other tanks. A 90 gallon community and a 55 gallon with discus which for sure, would have alerted me to any water problems.

All I can do is hope they spawn again and I'll be super diligent with feeding, water changes.