Who Gives A Fish Forums

My corals aren't extending like they used to. Tank is a 40 gallon with T5 lighting, running for about 8 months. Water params are good, 0 ammonia, 0 nitrite, 10 nitrate, 8.2 pH, 1.025 salinity. I do weekly 10% water changes with Red Sea salt. They're mostly Zoanthids and a few Acans. Any ideas?

Sounds like they're giving you the silent treatment, ha. But seriously, how's your flow? If it's too strong or too weak, they might not wanna come out. Also, what's your temp sitting at? Anything above 80 can sketch them out.

Furion wrote: ↑Mon Jul 28, 2025 4:44 pm Sounds like they're giving you the silent treatment, ha. But seriously, how's your flow? If it's too strong or too weak, they might not wanna come out. Also, what's your temp sitting at? Anything above 80 can sketch them out.

Flow's a big one. I had the same issue with my Acans until I tweaked the powerhead. They're chill now. What kind of flow setup you got?

Check your lighting schedule too. If it's too intense or not enough, they'll retract. I run my T5s for 8 hours max. Also, any recent changes to the tank? New fish, meds, or additives can mess with them.

I agree with BurningStar. Even small changes can stress them out. How long have they been closed up? If it's just a day or two, they might just need time to adjust. But if it's been weeks, something's off.

Thanks for the tips, everyone. Flow is two MP10s at 50%, temp is steady at 78. No new fish or meds. I'll try reducing the light duration and see if that helps.

Nice, MP10s are solid. Maybe bump the flow down to 40% for a bit? Sometimes they just need a gentler vibe. Let us know if they start peeking out.

Yep, flow tweaks can work wonders. Also, what's your feeding routine? If they're hungry, they might not extend. I spot-feed mine with Reef Roids twice a week.

FinFan wrote: ↑Mon Jul 28, 2025 10:44 pm Yep, flow tweaks can work wonders. Also, what's your feeding routine? If they're hungry, they might not extend. I spot-feed mine with Reef Roids twice a week.

Spot-feeding's a good call. Hungry corals are shy corals. What's your phosphate level? Too low can also keep them closed up.

Phosphate's a sneaky one. Mine dipped to 0.02 once and everything retracted. A tiny bump with NeoPhos got them back to normal. You testing for that?