Maybe it is the Ph. The remaining pair are still around and appear to be ok. I will look into RO supplies again. I might also syphon out the sand. The tank water is about 0.2 more alkaline than tap water which I don't understand.
I know it is hard water for Corys but these are tank bred fish and the supplier kept them in london tapwater pH 8. They seemed fine for the forst 4 months or so.
The substate is sand and I'm wondering if it's gone anaeriobic somewhere? Nothing visible but Ihaven't taken everything out yet. Should I just syphon it all out and replace with gravel? Other problem is algae. It's been quite bad, I've cleaned a lot of it away but there is still brown and green alage gwoing quite profusely. Blue green was growing where the vallis leaves float on the surface so i had to cut them back severely. I don't knwo why there is so mcuh algal growth, I thought iit was just part of the tank maturing but it's been going on quite a few months now.
Yes, I give them flake, catfish pellets (well obviously these ae supposed to be for the corys but the keholes eat them anyway), tubifix, frozen bloodworm, moaquito larvae, brineshrimp and daphnia. I'd say bloodworm is their favourite.
Anyway, 3 weeks in and a pair has formed, and today I notice eggs on a flat rock beneath a plant. The parents are guarding these quite effectively at the moment so we will see what happens.
The slight trouble is the 3rd kehole is getting a hard time from the two parents - I think I might have to re-home him.
After reading everything I could find on the internet I decided on keyholes. I picked up 3 juveniles today from Wholesale Tropicals. I am very pleased with them at the moment; they are intelligent, energetic fish that have already added something to the tank.
Time will tell if they were the right choice but I am hopeful. Here' two of them.