Long tentacle plate

i got a ltp coral about a week ago. it seems to be doing fine but sometimes he puffs up really really big. almost 2 or 3 times as big as normal, but usally goes back down to normal several hours later.
i have a 55 gallon and he is on the sand. my lighting it 4 t5ho 216w total.
should it be ok?
thanks

 

oh and just because people like pics this is it being "normal"

 

and this is him kinda puffed up, bad pic i know

 

That is a good looking coral.

I have a short tentacle and it does the same thing. It eats and has grown, so I don't worry about it.

 

should i be spot feeding it at all? i know its mainly off the light but im not sure.

 

Yes, they should be target fed periodically.

Be careful with what you put near them. When they inflate, Heliofungia can walk and they pack a pretty good sting.

 

ok they just eat photplankton or something like that right? or should i feed rods food?
i also put some rubble around it to try to box it in a little because i know they can move somewhat. will that work?

 

They don't eat phytoplankton at all. Mysis shrimp and krill would be what you're looking for. Rod's food will be good as a supplement. Heliofungia prefer larger foods.

If you keep him well fed, he's also less likely to wander.

 

another question.. how do you know when there eating? i did feed it the other day and it looked like it just went everywhere. it wasnt like it was grabbing the food.

 

The food was too small for it. Wait until 1/2 hour after lights out. Under moonlights or ambient light from the room, put some larger foods on it. It will grab it and pull it to it's "mouth".