Is your tank cycled? What are your test readings for Ammonia,Nitrite,and Nitrate? How long has the tank been set up? What are you feeding? Any other tank mates?
yes it is cycled it has been going for 3 months. I am getting testing strips tommorow. No other tank mates and feeding tetra flakes and some tetra crab and lobster bites about every 4 days
You might want to up that to every week. A small tank is much harder to keep stable. Is it heavily planted? Do you dose ferts? Do you have a heater? Whats your water temp? What kind of filter?
No heater but the water is 72 I am going to get a heater because it is getting colder. 2 Marimo balls, a small plant about 4" all around and no fertilizers and a i25 internal marina filter with a spnge over the front to avoid babies being sucked up.
How stable is the temp? A 2.5 gallon tank will rise and fall very rapidly with room temp. That may be the problem unless the room temp is very stable all the time.