Help with some problems

[ksteady]

First a backround on my setup.

90 gal planted
CO2 injected
Ferts once a week ( florish, pot, phos all recomended dose but only once a week )
Running 3 months
Florite substrate
undergravel heating as well
Eheim 2028 canister filter
78 degress

Water tested once a week with all good results every single time. PH sits around 7.3 I use strips every so often as a doouble check but am using API master test kit weekly for all 4 major tests.

Cycled with 13 zebra danois

adding a few fish a week I am up to
15 otos
pleco
15 shrimp
3 red back bleeding heart tetra
7 rummy nose tetra
3 panda cory
15 zebra snails
5 Furcatus Rainbow
3 SAE
2 Indian Flasher Barbs
5 Neon Rainbows
9 Cardinal Tetra
Pea Puffer
2 Julie cory

Ok. All has been going really good with my tank. I do a water change weekly of about 35% and dose ferts on same day with the new water. I have been seeing some troubles only within the last 2 weeks. 2 Weeks ago I added the 9 Cardinal Tetra's. I have lost 1 every few days or so and am down to 4. They all seem fine everyday and show no signs of trouble. I have heard they are kinda fragile when first getting them into a tank and have not worried to much about them. I took out the 13 Danio's 5 days ago as they were not part of my plans to begin with and I brought home the 5 Neon Rainbows the same day. 1 Neon that seemed really streesed did not make the first night. The following day I lost a Julie Cory. And today I lost 1 Indian Flasher Barb. With the Cardinals and the Cory I have not been near the tank at time of death to notice if they have been nipped at or what the problem may have been. Today when I got home the Flasher Barb was on his last hour of life. He showed no signs of nipping from others but seemed a tad fat and a really red patch on his belly. I have included a photo in hopes maybe someone has a idea of what may of happened.

I have 2 ideas they may not have anything at all to do with anything. I do not run air into the tank at all, however they do not show signs of need air over night. And the Pea Puffer. Would love to know your guys thoughts and hopefully the picture helps. I know you guys like numbers from the tests. I just finished a 50% water change and will post numbers tomorrow as I am due back at work in 7 hours. Last test was 3 days ago and everything was bang on. Filter was cleaned last about 6 weeks ago in fish water, just the 2 pads. If you guys need anymore info please let me know, off to bed for me and I look forward to any light you guys can shed on my problems.

 

[ksteady]

Oh forgot about the food. I feed a pinch of flake and a pinch of shrimp pellets once a day.

One other thing comes to mind, being a large tank it took me near 45 minutes to round up all 13 danios I took back and this maybe added stress to the tank ? Although i was losing the Cardinals before this.

 

[Dano01]

You have a conciderable bio load in your tank.....Are you sure of the ammonia readings?......Are you metering the co2 where you are confident that there is sufficent oxygen left in the water?

 

[bs6749]

You have a conciderable bio load in your tank.....Are you sure of the ammonia readings?......Are you metering the co2 where you are confident that there is sufficent oxygen left in the water?

That's not a considerable bioload at all for a 90g tank, let alone a planted tank with CO2. I highly doubt that ammonia is the cause of this because the plants would soak up the waste, not to mention that the snails would all be up at the surface of the water and the shrimp would be some of the first to die.

It's also not a lack of oxygen in the water since fish are slowly dying and not all at once. If it WERE a lack of oxygen the pleco and danios would be left since they have a labyrinth organ and can gulp air from the surface.

More likely the fish died of "natural causes". The flasher looks like it had septicima or a bacterial infection from the redness and swelling. The cardinals were most likely wild for being bought this time of year and they are harder to keep alive than commercially bred ones, which don't account for many on the market.

In short, I wouldn't be too concerned with the recent string of bad luck. It may be a good idea t do a 50% water change to remove any possible pathogens from the tank and it's also important to keep an eye on your water parameters, though I suspect they are all in line because of the plants.