What should I be feeding my coral polyps?

[bloojeanz]

Hi, I have two types of coral polyps in my tank, the first pic shows the larger ones which are doing really well. The second pic shows the smaller ones which have been slowly shrinking back over a few months. I have been feeding the first ones (freebies with my live rock!) with mysis, squid etc but the second ones (zoanthids??) I was told didn't need feeding. I have had them about six months but they really aren't doing very well now. I can only assume that they aren't getting the nutrients they need, should i be feeding phyto-plankton or something? Thanks in advance for your help!

 

[bloojeanz]

Whoops! Where are the photos? I will try again, sorry!

 

[bloojeanz]

Here are the smaller ones which are slowly shrinking!

 

[loganizzi]

what is your lighting like?

 

[bloojeanz]

Lighting is fairly low. 2 NO white actinic and 1 NO blue, tank is 18" deep. I was told that the polyps wouldn't need strong lighting and they haven't lost any of their colour (symbiotic zooanthe?). Do you think lighting might be the cause of them shrinking? I have had them about six months and for the first 4 months they looked great but over the last few weeks they have shrunk considerably. Is there anything I can feed them with? The larger polyps (freebies!) appear to have a mouth and can engulf quite large chunks of meat but these are different.

Tank is as follows -

48x18x12
SG = 1.023
ammonia = 0
nitrite = 0
Nitrate = 0 ( could this be the problem, Is the tank too clean?)
Calcium = 400
Dkh = 17
oxygen = OK, can't remember exactly
Phosphate = 0

Any help would be greatly appreciated!

 

[Salt4Us]

I'm no lighting expert, but I've noticed that the places that sell zoanthids (your polyps on the bottom of your tank) usually have higher lighting. You might try moving them up higher in your tank and see if that helps.

Nice looking zoanthids btw

 

[HoopsGuru]

According to Eric Borneman's Aquarium Corals book, different species of zoos have different lighting requirements. The ones with a longer base and longer tentacles are built in such a way to stick out in the currents and capture foods. The ones with a shorter base and shorter tentacles rely more on their symbiotic algae.

Judging from your picture, I would say that the polyps that are not doing well should be placed much higher in the tank to see if this would help, they appear quite stout with broad caps and short tentacles for obtaining as much light as possible.

0 nitrates is not the source of the problem, and is actually a good thing!

 

[loganizzi]

since all your parameters look to be in order, and from the picture it looks like they are sitting on the bottom of your tank. I would try moving them up a third of the way to the top. See how they do after a week, and then move them up another third the next week, and finally to the top by week three.

 

[bloojeanz]

Thanks guys! I will try moving them higher up and see how it goes. Any ideas on feeding them? I have tried drifting small pieces of shrimp etc over them but they don't seem capable of catching it. I have also tried basting them with a liquid feed ( liquifry marine ) but that made them close up for three days so I guess they didn't like it! Perhaps they really don't need direct feeding and just require more light.

Thinking back, they only started really shrinking when I moved them to the side of the tank where there is less light, I could of worked that one out for myself! Doh! I am not normally that stupid, honest!