I am thinking of a species tank or either goldfish or tiger barbs, and the tank would be between 20 to 30 gallons (most likely close to 30).

The goldfish, when grown, would be moved to a pond, and I have a huge pond unit, so there will be no worries about space while they are small (thinking of black moors and colorful fantails, maybe three goldfish in total).

I also like how tiger barbs look and their aggressive nature (not so much into fish like neon tetras :P). Was thinking of a fully planted tank with wood and nice lighting and a shoal of them, maybe mixing with some green tiger barbs.

Which do you think will be most rewarding/attractive/fun?