Not great and very little advice, but I'll try anyways.
If they are Tubbs Blues which are the most popular, the standard advice I've read is that they are slow growers and prefer shaded (of course depends on your lighting) conditions. They could be anyother type of cool expensive zoa too though. They seem to be more and more prevalent. So the general advice I'd give is to make them happy. If they close up in their current location, try somewhere with more or less light, more or less flow, etc. until you find the spot they like the most. Good luck with them, I'm sure they're beautiful!
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8G Peacock Gudgeon, 75G CA/SA cichlids, 120G Planted, 50G Mixed Reef (
Build). 125G Reef and 100G frag tank in process.
Save the reefs... Buy captive raised when possible!