MUTARIUM: Mutant Aquarium Defense

What you feed is your build.

MUTARIUM is a feed-and-defend roguelite. You run a lab aquarium full of specimens that mutate based on what you feed them — and the lab's failed experiments keep breaking in to eat everything you've grown.

You never command your fish. You feed them, they fight. Every pellet is a build decision.

• Three feeds, one build — MEAT makes killers, GLOW makes earners, ORE makes walls. The mix decides each fish's mutation branch: pure lines, hybrids, and a KING rank for those who push their luck.
• Read the forecast, change the diet — every wave is announced before it hits. Chargers punish your shots, spitters hit from outside your tank line, splitters punish your finishers. Your counter-pick is what you feed next.
• Overfeeding is real — max out a specimen and keep stuffing it, and it goes berserk. Your best fish becomes the invader. You made it; now deal with it.
• Bosses drop sealed specimen eggs — hatch them to unlock new species (Guppy, Leech, Ironjaw, and one still sealed), each with its own mutation tree and a codex to fill.
• Short runs, long descent — a run is one dive through the facility: the Isolation Tank, the Deep Vats… and four sealed floors below. The elevator keeps going down.

Heads-up on tone: mutation is cartoon body horror. Specimens visibly deform and grow clustered eyes as they advance. No gore, no realistic injury.

Insaniquarium invented the feed-and-defend aquarium in 2001, and nothing has carried it forward since. MUTARIUM is a love letter to that genre — rebuilt as a roguelite, where the feeding itself is the build.