I’ve had my 29 gallon going for a little while now and it was doing great. It’s stocked with 3 blue rams, 9 pencilfish, 3 ottos and 2 dwarf gourami and a black mystery snail. Ammonia 0, nitrite 0, nitrate 5. Ph 8. Everything was doing good until I added 6 rummynose tetras 4 days ago. One of them...