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My Yellow Tang has been flashing against the rocks a lot lately. Tank is a 75g, parameters are stable, 0 ammonia, 0 nitrite, 10 nitrate. Salinity at 1.025, temp 78F. Only change was adding a new powerhead last week. Anyone seen this before?

Flashing can be a sign of parasites. Have you checked for ich or velvet? A fresh water dip might help if it's external parasites. Also, how's the flow from the new powerhead? Too strong might stress them.

Yo, my tang did that once after I messed with the rocks. Turned out it was just scratching an itch, lol. But yeah, keep an eye on it. Maybe cut the flow a bit?

Ravyno wrote: ↑Sat Aug 30, 2025 9:52 am Flashing can be a sign of parasites. Have you checked for ich or velvet? A fresh water dip might help if it's external parasites. Also, how's the flow from the new powerhead? Too strong might stress them.

I agree with Ravyno. Parasites are likely. Have you added any new fish recently? Could be introducing something.

Mine did this when I had a tiny ammonia spike. Even if your params look good now, maybe test again to be sure. Also, how often are you doing water changes?

Tangs are prone to stress. Could be the new powerhead. Try adjusting the flow or moving it. Also, what's your feeding routine? Hungry fish get weird.

bruh, my tang was flashing like crazy till i turned down the lights. maybe yours is just vibing wrong with the lighting. just a thought.

Thanks for the suggestions, everyone. I'll test for parasites and adjust the powerhead flow. Didn't think about the lights, luminox, but I'll check that too.

Hampuk wrote: ↑Sat Aug 30, 2025 5:40 pm Thanks for the suggestions, everyone. I'll test for parasites and adjust the powerhead flow. Didn't think about the lights, luminox, but I'll check that too.

Good plan. Let us know how it goes. Parasites can be sneaky, so a quarantine tank might help if you confirm it.

Also, consider adding garlic to their food. It's not a cure, but it can boost their immune system. I've had good results with it.