[Chin_Lee]

MODERATOR - please move to Reef Discussion if its more appropriate now

In my quest to rid my tank of bubble algae, I've come across two fish that i have success in eating valonia. One of them is a large sailfin tang. I acquired a large one locally and it eats valonia quite readily. However this fish grows rapidly and get very large. The one I acquired is about 6-7" and when its "sail" fins are expanded, its easily 8-9" high. I placed this species into my 300g tank which I feel is living well in the extra space available. Putting one of these into a small tanks may not be an option for many.

The second species have been the rabbit fish but caution must be used with them because they are not all created "equally". I have had good success so far with the 2 out of 2 Golden Rabbitfish (Siganus corallinus). I bought one that was 2.5" and a larger one that was 4" and they both eat bubble algae AND hair algae.

Caution: I had bought another rabbitfish Bluelined Rabbitfish (Siganus puellus) that was odd in that it would hide all day and nip at my Lobophyllia corals. The person I bought it from had also cautioned me about this fish in that it would also nip at his ricordias and mushrooms. I had to recatch this fish and donate it to a LPS. On the other hand, while at this LPS, it had an identical Signaus puellus in the display thank that was full of LPS including lobo and rics.

My recommendation for any aquarist having issues with bubble algae and hair algae is the rabbitfishes. When buying one, make sure its out and about swimiing in the open. Avoid the ones that cower in the corners or in the rocks. Before introducing it into your diplay tank, (and if possible), put your newly acquired rabbitfish in the sump at first and place some frags of frogspawn, lobo, mushrooms into the sump as well. Also put a rock with some nuisance algae to see if it will eat it. You should know within a few days if its a keeper.

PROS:
- will likely eat bubble and hair algae
- most are quite colorful
- although some will grow quite large (do your homework before buying), most will stay around the 5-7" range in captivity
- relatively inexpensive and commonly available

CONS:
- some may nip at corals softies and LPS (many reports the disappearance of xenia, anthelia, hair algae, bubble algae with the introduction of rabbitfish into their tanks)
- some may be shy and hide (you can tell from the store depending how long they have been in the LPS)
- some can grow very large (ie orange spotted beautiful but can grow up to 16")

As far as the emerald crabs are concerned, even if they are effective, due to their sizes, I believe they can only eat one, two and possibly three valonia in a day. A good sized Rabbitfish shoud be able to devour at least 10-30 bubbles while grazing.

Hope that helps.