Aggressive Stocking ideas for a 75 gallon

[crayfishlobster]

Snakehead or lots of exodons

 

[J. H.]

Sunfish, puffer, or go fowlr. You can get real nasties if you go fowlr, and it is not always so expensive.

 

[Gourami Swami]

Probably the "meanest" freshwater fish for this tank size would be a shortbody flowerhorn. Large grammodes are mean too but take forever to grow and are shy as youngsters.