Tank of Death

[FishieMomma]

Two more "random" tank deaths yesterday. Down to 2 frequently breeding koi angelfish who seem to be healthy, 2 male guppies, 1 platy and 2 Corys and 12 neon tetras, who have thrived since I first stocked the tank a year ago.

Ammonia, Nitrite 0, Nitrate 10-20 API Master Kit
Fishless cycled a year ago, 40% PWC 3xs a week!
Only chemical used is Prime
Two Aqueon 70 filters
55 gallon
2 heaters
thick gravel substrate
3 real plants

The only thing I can think of is that the gravel substrate isn't cleanable enough. I think i am doing ample PWCs.

Any ideas?

PS: The tank is kept consistently at 80. I temp match my water when adding it. The platy that died yesterday was "gasping" for a few days prior to death (even after 40% PWC) but not at the top of the water. No visible signs of injury or sickness. The Cory that died had worn down barbells from the gravel (which was going to be replaced next week when hubby is on a biz trip, anyway) but no signs of sickness or injury, either.
PPS: no signs of flashing, either. I feed a smidge of foods every other day.

 

[Ed Stansbury]

I think we all hate random fish deaths (and we've all had them), and they do make it hard to find the causes. But the breeding angels would indicate that there's nothing too seriously wrong with your tank conditions.

In general, labored breathing is associated with gill flukes or capillary aneurisms from ammonia-burned gills. Both are common in store tanks.

A couple of questions on general sanitation...
Is there a reason for the heavy gravel layer? Just makes a reservoir for decay.
And when you do siphon, are you siphoning the entire bottom and bringing up gunk? It should always appear to have minimal debris.

If you're using back filters, there's no biological reason to have more than a skim of gravel. IMO, sand is a much better choice than gravel.
The only time a one or two inch or so layer is used is with coarse gravel and UGs.

Hope that helps.

 

[Mumma.of.two]

Are you sure the angels aren't killing them? Breeding angels can get pretty nasty. Perhaps the platy could have been bullied to death.

 

[FishieMomma]

Thanks for the replies. The thick gravel layer was for decoration, like making different heights of gravel for a more "natural" look.

I just now finished re-doing the entire tank. I put all the fish in a huge bucket with tank water and a heater and drained the whole 55 gallons! Then removed ALL the gravel (and it was gross!). Even though I always thought I was cleaning it with the siphon tip I guess there was more debris trapped in there.

I wiped the tank down with paper towels and put in black sand from the pet store. Then refilled with Prime-conditioned water and added the fish and plants back in.

So now there is only a thin layer of sand on the bottom. I know I have to be aware that removing all the gravel may trigger a mini-cycle. Or maybe even a major one! So I'll be checking the parameters daily. The tank is very lightly stocked so hopefully that will help make it less dramatic a cycle.

As far as the angels bullying, they do nip when the other fish come by when they have eggs. (don't worry folks, they are about to lay but haven't yet so I didn't kill any eggs.). I didn't think they were being too aggressive but I'll watch more closely.

 

[FishieMomma]

Here's the new tank.

 

[Greenphantom]

Dang I have a 120 gallon tank and it sprung a leak so I went and resealed the whole tank and changed substrate from gravel to black sand I started a the cycle process over nitrates spiked and I lost alot of fish but I caught it and if you do large daily water changes it will make it much easier on your fish I am just telling you this so u are aware test daily for the next week

 

[FishieMomma]

Thanks, my friend!