Hello. Got a rio 400, 1 oscar, 4 dollars and 1 texas. Got the chance of either 1 severum, a breeding pair of sevs, breeding pair of parrots or a couple more dollars.Is my tank ok for more fish. Current mood in the tank is great and they all get on fine. Will it rock the boat adding new fish. Ive heard that sevs when breeding can be quite nasty. Any experience out ther of this please. It has two externals so filtering should be fine.

Many thanks.

if i remember correctly a rio 400 works out to be about 90 gallons or so. with an oscar and a texas already in the tank along with 4 sd's i would stay away form any breeding pairs. a few more sd's or maybe a single sev is all i would add to avoid overstocking.

adding any new fish to an established tank is a risk. all fish have different personalities so there is really no saying in what could happen.

whats the measurement of a 100 gallons tank in inches??i have a big tank but im not sure if it is a 100 gallon tank...

a 100 gallon tank would measure something like 60x18x24 inches

As what Necromancer said,"Silver Dollars are your best bet for that tank" I would do that too if I was you Parrots or any Severums that breed you are in trouble your Oscar will be killed even as soon as you put a breeding pair in.So as probably anyone will else will do put Silver Dollars in a few more and you should be fine.

Cheers guys. Luck would have it. Was in my local fish shop and in one of the tanks, he had a single silver dollar that looked really lonely ! So paid me money, and home he came. He has settled in a treat with the others. Hes a tad smaller but looks a treat. Must post some pictures, tank looks a treat.