- Reaction score
My brother has a 3.5 gallon with zebra danios, neon tetras, a betta, and ghost shrimp. Today all the neon tetras were dead but they had no sign of nipped fins from the betta. The tank has no heater and I tested the water and got 80 hardness and alkalinity, 7.3 PH, 10ppm nitrite, and 0ppm nitrate. I'm guessing it is either ammonia or temperature.