Hello, I have a 125ltr tank with a Fluval U3. Current stock includes 5 Cory, 6 Celestial Pearl Danio, and 8 Lambchop rasboras. I would like some bigger mid/high swimming fish preferably with colour. Any ideas please? I did try an Agassizi but he didn't live long (my PH is 8.0 which is probably the root cause, all other levels fine in mature tank/filter).