Is my puffer fish sick?

[Vitalix]

I'm in a bit of a bind here. I know, I know, no quarantine tank - stupid mistake. My husband and I just got a Porcupine Puffer, like 3 days ago. He seemed fine when we got him, but now I'm worried. Yesterday and today, his color's been off, and there's this weird white patch on one side. I've seen ink before, but this is different. I can try to post a pic if that helps. The thing is, I haven't seen him eat yet. And he's just floating around, sometimes at the top, sometimes at the bottom, but mostly just stuck in the corners. That's not a good sign, right? I had a fish tank before, and when my fish did that, they didn't last long. If someone could please help me out, I'd really appreciate it. Any ideas what's going on with my puffer?

[fleeton]

Honestly, it's probably too late by now, but without pics, it's tough to advise. The behavior you're describing doesn't sound good - usually when fish act like that, they're beyond saving, even with meds. I wish I had some better advice to offer, but it's not looking great.

[coltin]

I think putting it in a quarantine tank would be a good idea, and offering live brine shrimp might encourage it to eat. If it's being bullied by other fish in the tank, being alone could help it feel more at ease. The live food might also stimulate its appetite.

The white patch on its side could be a sign of a skin parasite, poor water quality, or maybe even fungus from being handled roughly. Isolating the fish would also help prevent any potential disease from spreading to the rest of the tank, and if the worst happens, it won't affect the other fish.

[DarkHive]

I'm thinking the stress could be from when they netted him at the shop, maybe they lifted him out of the water and now he's got air trapped inside, that can be really tough on them.

[flumix_9]

Check your nitrates, porcupine puffers have skin like loaches, not scales, so they're really prone to diseases from poor water quality and other stuff. Hope this helps. What's the tank size and parameters, by the way?

[zenoxa]

Nitrates would need to be extremely high, likely over a few hundred ppm, to have that kind of impact on the fish. The lack of scales doesn't necessarily make them more vulnerable to nitrogenous wastes.