Well, I just hit level 100 and I could go on forever(I think).
The build evolve over time but my specie got 3 role. I will only put the man attribute.
Specie 1 : hunt enemy, give xp to other on death(this is realy important), I keep spamming this species and I keep it cheap. Slowly make it into a strong tank. At stage 100, it had 40 hp, 8 str, 4 spd
Specie 2 : Stay in the center, make other specie each 30 sec, spawn at each wave. At stage 100, 3 would spawn each wave with 3 baby. They cost 21 but I never have to make them. They would make so many of the other fish that I rarely had to make any.
Specie 3 : Get fishy, make and shot bubble, give xp to other on death at later stage.
Hey, really nice achievement! Hope you had fun and it didn't start lagging too much once you got this far.
Since this is a jam game (made in 9 days in a work week) there's definitely some balancing left to do and we will probably do one final update after the voting period of the jam is over. Ideally, we would want the difficulty to continue scaling such that it isn't possible to go on forever.
It's definitely not easy to get this far, most people struggle to get past wave 30ish, so again, nice achievement, well done!