CUC is really helpful to keep the tank clean. Without it the live rock just seems to get brown and unappealing. One issue you’ll run into is the Melanurus wrasse eating your snails. I have one now and it’s a great fish in every way except that. I add snails at night and give them a head start. I also keep conchs and urchins because the snails still disappear.
One downside to adding a CUC is that you can’t treat the tank with copper if you introduce a parasite. You already have nems so you’re already there. Just underscores the importance of good quarantine practices.
I think tangs could be a good next addition but with two cautions:
One, if you haven’t strictly quarantined everything going in to date, there’s a chance you have crypto in the tank even if it’s not showing. Adding tangs, which are parasite magnets, could turn an asymptomatic low presence into a full blown outbreak. Treating the tangs (or buying pre-treated or captive bred) and introducing them with an acclimation box to minimize aggression and stress will help but is no guarantee.
Second, tangs can be absurdly aggressive. A school of small captive bred yellows won’t bully your existing fish but a large blue tang (or any acanthurus species) likely will want to be the alpha. I find two solutions to that - either let it be the alpha and make sure it’s your biggest fish and the last you add or put a true alpha in above it on the peck order. I recently put my 6” alpha mimic tang in his place by adding an 8” emperor angel and it seems to be working well. I’m not sure that would work with a true bully like a clown or sohol tang.
Other fish to consider for a fish only are puffers and triggers. They can eat your CUC but some triggers like blue jaws, crosshatch or Niger triggers are pretty safe. Small puffers like Valentinis are a small risk but a big dogface would likely make short work of the CUC and nems.
I think you can also add more angels but with some risk of aggression between them. If you want to add one more, I’d go with a larger adult that won’t be bullied by your large juvenile Koran.
Butterflyfish would look great without taking up much space or creating major aggression issues. The risks with them are they might be bullied by similar sized tangs or angels and you need to pick species carefully. There are a lot of bfs that are notoriously difficult in captivity and really shouldn’t be tried or should only be tried in a reef tank with corals you’re ok with them eating. Good species for your tank would be burgess, declevis, tinkeri, raccoons or semilarvatus if you can find them. The first three are hardier and stay smaller. You should also read up on the species before buying to get a handle on how likely they are to eat your nems. A copperband would likely make quick work of them. The burgess, declevis and tinkeri should be safe. Not sure about the raccoon or semilarvatus.
With any new addition, I’d highly recommend slow introduction. If you have room, after quarantining, I’d give them a few days in an acclimation box so the other fish get used to seeing them before they can interact.
I've kept pink square anthias before and liked those a lot. I guess I can't have it all. Puffers I like are out of the question if I want the CUC. So you've led me in the right direction, and given me some fizh options I had not thought of. The Koran angel just keeps growing and growing, but it's juvenile coloration/stage has not changed at all. It started out the size of my flame angel and is now the sane size as my foxface. As long as it remains healthy, Im not too concerned. Thanks again! Appreciate it!
