An anemone would be sufficient if the clown fish will host with it. However, anemone bring with them their own issues. A second clown might help as well since they will pair up.

 

Is the gramma actually attacking the clown or just mock charging it? Does the clown have any torn fins or any other visible signs of injuries?
In a 55 there should be plenty of room for a clown and gramma to live together peacefully. The gramma may try to run the clown off from its territory, but I can't see it actually attacking the clown.

 

The gramma sure seemed to be making contact with the clown but the clown doesn't have any marks of it. Today, it looks like the clown has learned his place and is adapting and not getting charged so much so hopefully it stays like this. I think I'll get an anemone or one of the stinging corals this weekend anyway.

 

No need to get an anemone to protect the clown. Royal grammas like to charge 99% of the way, but mine have never made contact with another fish. A clown can show it's damsel lineage if it really get attacked.
A duncan whisker coral will also be a good host for a clown, and would be much easier to car for.

 

Not trying to hijack the thread, however, along the same lines.

I plan on putting a royal gramma in my 29g which already has a clown, is there sufficient space in there for them to coexist? I have many nooks and crannies in the LR as well as corals for safety.

 

Proseph-FWIW, I have a 46g bow and my gramma likes to stay on the side with the pair of clowns(ocellaris, A.) without any problems. My clowns tend to be the aggressors, they were introduced first so they own the tank. I had to move my clown goby to another tank because the pair of ocerllaris' were nipping at him though. I also have a dragonette, blenny, and a six line and they all live very happily together.MrDesjardini- I think it's like john said, if the gramma is really nipping, the clown' true colors will show(depending on there sizes). there's no guarentee that it will host, but when they do it's a really awesome site, I wish my clowns would go into an anemone but when the female was in a tank with a large rose bubble tip anemone she just stared at it and ended up hosting the powerhead, or the powerhead hosted her haha, but anyways good luck with the nem.

 

Clowns can be persuaded to host. I do this by feeding them close to the anemone, moving a little closer each day, then eventually right over it. They begin to brush against it and pretty soon are inside of it. I have to agree with Iron Trees that when they host, it's really awesome.

 

I have a two Oce Clowns black and white and added a gramma shortly after.

The Gramma did the whole open mouth mock charge and made barely contact numerous times for over a week. The gramma mostly did it to the male clown. Finally the female got tired of it and had words with the Gramma and it never happened again. Since then the clowns have a nest site and a mushroom bed they host to, and the gramma stays with them as a pack all day long. They are okay with each other and swim together all the time. The clowns even let the gramma use a crack in the rock where their "nest" site is to sleep. (Keep in mind nothing is allowed there by the clowns, my hand is not allowed, Snails are not allowed, hell they try to get the urchin to leave if he wanders there) But now the gramma is like family.

Now last weekend introduced a tiny cherub angel, The gramma resumed his open mouth threats. The gramma is 2x the size of the angel but the angel stood his ground and set him straight a few times and the gramma has gotten used to the angel. The angel has no fear so the gramma has given up and usually hangs out with the angel and keeps an eye on his constant activity


Open mouth fake charging or even touching with an open mouth is all just threats and posturing. Its mostly the gramma trying to be dominate. Two things to watch for with a Gramma is if the aggressiveness is being triggered when its near the gramma's home/hole/sleep spot. That could be territorial and moving rock around can lessen it. The other thing is that the Gramma will open mount then bite or clamp down on another fish. Gramma's fight each other by interlocking mouths and clamping down on each other. So charging 99% and not biting or clamping down on a fish is just them trying to be dominate.

 

For the first time since getting my Royal Gamma a little over a month ago, I just saw him do the whole "open mouth" aggression thing. It kinda freaked me out because I had never seen him do it. The darting was pretty normal if he got pissed off/scared, but the gaping mouth was weird.

I have mine in a 20gal with 2 paired Oc Clowns, Green Mandarin, Peppermint Shrimp, and some CuC. He was added after the 2 clown and before the Mandarin, originally he kept to his side of the tank (the right) but he's gotten much bolder over the last week. He now regularly attempts to steal the Clowns food, Formula 1 Pellets, which he doesn't even like! He just grabs it and spits it back out on the bottom (which the Peppermint Shrimp promptly devours). The Clowns, although the original "owners" of the tank seem to be dominated by him for now. The Mandarin and him get along fine though, I've never really seen any issues there, though I guess that's because the Mandarin isn't going after his food.

Also of note - my 2 Clowns are hosting my heater. It's pretty funny looking, but they protect that thing like no other. They only swim away in the mornings and sometimes to feed.