Green Spotted Puffer

1) Where they come from

Green Spotted Puffers show up all over South and Southeast Asia—river mouths, mangroves, and coastal areas where fresh and salt water mix. That “in-between” habitat is the whole story with this fish: they’re not really a freshwater puffer long-term, even if the store tank says otherwise.

2) Setting up their tank

Give them space and clean water first, decorations second. A cramped GSP gets spicy fast, and dirty water shows up as fin issues, cloudy eyes, and general grumpiness.

• Tank size: I wouldn’t bother with less than 30 gallons for one. 40B/55g makes life easier if you like scaping and want stable parameters.
• Filtration: over-filter it. They’re messy eaters and produce a lot of waste. A big HOB or canister + prefilter sponge is your friend.
• Substrate/decor: sand or fine gravel, driftwood/rock work, and lots of sight breaks. They like to patrol and “own” areas.
• Plants: brackish limits you, but you’ve got options—Java fern, Anubias, and some Crypts can handle light brackish. Mangrove props look cool too (slow growers).
• Salinity: use marine salt mix (not aquarium/table salt). A refractometer is the nice-to-have tool; a hydrometer can work if you’re careful.
• Temperature/pH: mid-to-upper 70s°F is a comfortable zone. They’re generally happier with harder, more alkaline water than soft/acidic setups.

3) What to feed them

They’re basically little beaks with fins, and that beak never stops growing. Your job is to feed foods that wear the teeth down, not just soft stuff that turns them into a dental emergency.

• Staples that help with teeth: ramshorn/pond snails, Malaysian trumpet snails, small clams/mussels (in shell), cockle, and chunks of shrimp with shell on.
• Frozen foods they usually go nuts for: bloodworms (treat), mysis, krill, chopped prawn, squid pieces.
• Live foods: snails are the big one. I’ve also used ghost shrimp as an occasional hunt/enrichment.
• Foods to go easy on: lots of soft, shell-less foods only (leads to overgrown teeth), and fatty feeders like goldfish (also disease risk).

4) Behavior and tankmates

Green Spotted Puffers are smart, interactive, and absolutely willing to bite the wrong roommate “just to see what happens.” Some individuals are manageable, some are tiny sharks in a green suit.

• Temperament: curious, territorial, and nippy—especially as they mature.
• Best kept: solo, honestly. One puffer in a nice setup is a stress-free win.
• If you try tankmates: think fast, robust, and brackish-tolerant. Even then, have a backup plan and extra tank ready.
• Never with: long-finned fish, slow fish, or anything you’d be upset about losing. Also skip snails/crabs you want to keep—they’re food, not decor.

5) Breeding tips (realistic expectations)

Breeding Green Spotted Puffers in home tanks isn’t common. Sexing them is tricky, and they tend to want room, seasonal cues, and a setup that’s basically dedicated to the project.

• If you want to try: plan a species-only tank and grow a group of juveniles (6+) to hopefully end up with a pair.
• Conditioning: heavy feeding with meaty foods plus excellent water changes.
• Spawning behavior: males can get more territorial; eggs are typically placed on a surface and guarded (reports vary).
• Be ready: adults may bully hard during pairing attempts—separation/dividers save fish.

6) Common problems to watch for

Most GSP issues I’ve seen come back to three things: wrong salinity for the fish’s age, not enough filtration/water changes, and teeth getting out of hand.

• Overgrown teeth (beak): the puffer stops eating or can’t crush food. Prevent with shelled foods/snails; once it’s bad, you’re looking at trimming (vet/experienced keeper territory).
• Ich/parasites: puffers can be sensitive to some meds (especially copper). Quarantine new fish/food sources, and read medication notes carefully.
• Fin damage: usually from nipping (tankmates) or the puffer scraping itself on sharp decor during feeding lunges.
• Ammonia/nitrite spikes: messy feeding + under-filtered tank. Puffers show stress fast—clamped fins, hiding, heavy breathing.
• Wrong salt: using “aquarium salt” instead of marine mix doesn’t give the right minerals and stability for brackish/marine conditions.