okay thanks the spanner is 5 inch and fully grown ? and seems very content in the tank and is that reaaly all i could have in a 55 gallon tank seems a bit empty thanks
Alex
Spanner's get 8 inches, and they are active fish that deserve a 75 gallon minimum.
Fish may seem "happy", but it is never true. Unless you learn to speak fish, it can't tell you.
Abused dogs will still wag their tails at their abusive owners. Dolphins have that permanent smile on their face, even if they are in a tiny, dirty pool.
You could always add another group of schooling fish to fill up your empty tank.
A school of 8-10x Praecox Rainbowfish would look splendid alongside a school of 12x Congo Tetras.
You could, if you have sand, also get a school of cory catfish.
1x Angelfish
4x Platys
12-14x Congo Tetras
8-10x Praecox Rainbowfish
12x Corydoras catfish
1-2x Bristlenose pleco
Even with a 55 gallon, and filtration and weekly water changes, this is pretty much the limit of how many fish you can have.