Quick Help: Rainbows dying!
I could really use some feedback. I have 4 tanks and I keep a variety of other fish including angels, dwarf puffers, otos, various tetras and rasboras, CPD's, an African butterfly, and a pleco. I haven't had problems with any of those fish but I recently started a rainbowfish tank. It's been running about 5 months, fully cycled (I used cherry barbs to cycle).
55 Gallon, heavily planted but with lots of free space along the front. Temp around 28, PH always between 7.4-7.8, GH 6, KH usually between 6-8, injected CO2.
I put in 10 Threadfin rainbows and 6 Turquoise rainbows last week. Within a couple days the threadfins started dying. Then the Turquoise started. When I did a water change I used water with a lower KH thinking the PH might be the problem so it's now KH 6.9 and KH 4. Yes, the ammonia and nitrites have been 0 through all this.
I've been feeding a variety of flake, daphnia, frozen bloodworms (I know too big for the threadfins), and frozen rotiphers.
When I got down to 4 threadfins and 4 turquoise left I moved the threadfins to my CPD tank thinking maybe I was feeding too large of food or they were just not competing well enough with the turquoise. I also let the temp in the turquoise tank drift lower from 78 to under 77, thinking maybe it was too hot for the turquoise.
This morning all threadfins are still OK in the CPD tank, but I lost another turquoise and one of the others is not looking good.
I've tested the water and wracked my brain to figure out why the turquoise are not doing well in their tank. I do have 3 java rice fish in that tank that are doing fine through all this so I don't think there's anything else been introduced that would be poisoning the fish. Any help would be greatly appreciated!!! Suggestions?
65G tall planted community Tank
2 55G, 1 with larger rainbows one with smaller rainbows and CPD's
2 breeding tanks (with CPD and angelfish fry)