Tank Tank parameters
Heater by Fluval
90 gallon U3 filter also I believe by Fluval
Water has been tested by myself and my local aquarium store and has normal (7.0) ph, 0 nitrates, etc.
Tank has been set up for 1 year 1 month, although substrate and fish transferred from previous smaller tank which had been set up for 2 years
Temperature is steady and within normal parameters
Food: freeze dried daphnia and blood worms for loaches
Planted aquarium- a lot of plants
Light is on for 12 hours a day, there is some minimal sunlight that does come in around midday
Water changes every week
I use Seachem Neutral Regulator and Start Right Fish in tank (currently)
: 2 neon green raspboras, 1 cardinal tetra, 3 Endlers, 4 kuhli loaches, 3 shrimp, 1 furcata rainbow, 4 blue raspboras, 3 green tetras, 1 jelly bean tetra, some baby Endlers.
Problem: Recently my Endlers, traditionally some of my hardiest fish, started dieing one by one (there had been 12 and now there are 3). I had not added any fish, and the fish I had had been in there peacefully thriving for around 6 months (that was when I had last added any fish). Then other fish started dieing as well: a couple of the raspboras have died, and almost all my cardinal tetras and some of the jelly bean tetras. None of the fish that died had ick and none of the fish in the tank alive have ick. Each fish looks perfectly healthy when alive, and even after dieing does not have any red spots, white spots. discoloration, etc.
The problem is confusing me and my local aquarium resources, first because the fish which have been primarily dieing are my hardiest fish- the tetras and Endlers. And while some of the Endlers were a little older, a lot of the ones that died were less than 6 months. The more delicate fish that I would expect to die first if there was any kind of problem (the raspboras) have had some casualties, byt are by far the lest affected. My water has been tested and it looks great- and I have been told that my shrimps would die first if there was a water quality issue, and none of them have died. At the aquarium store we did more tests than normal to test for high levels of certain elements which can build up in the tank and be detrimental, and none of those tests registered a problem
So my fish are slowly dieing one by one and I don't know what to do! I am not even sure what the problem is! All the fish look healthy until I come home or wake up to find them dead.