The Sun Corals, Tubastraea species (Tubastraea sp.), are large polyp stony corals (LPS coral) that are moderately difficult to care for, but quite popular in the hobby.
If you take one look at these corals, you totally get why they are called sun corals. The polyps are round, fleshy and bright yell0w and orange and look a bit like the sun. But in true reef irony, the sun corals are non-photosynthetic, which means they don’t get any of their nutrition from the light of the sun, or in our case, from our aquarium lights.
Because they are non-photosynthetic, the sun coral is a perfect coral to add to those dark and marginal areas of your tank, to add a burst of color to the otherwise dim spots in your aquarium.
In the ocean
Sun corals are usually found in tropical and subtropical rocky and coral reefs all across the world’s oceans and seas. They are most commonly spotted in deep shaded areas such as crevices, pier pilings or caves. They also build their colonies on artificial surfaces like pillars or ship wrecks. While all corals are dependent on the flow of the ocean to bring dinner to them, the sun coral, being non-photosynthetic, is completely dependent on capturing food to survive, unable to get a free meal from commensal zooxanthellae.
In the aquarium
Sun corals are not aggressive and will do well with most other coral species, if given sufficient room. Because they are non-photosynthetic, you can place them successfully in dimly lit regions of the tank.
In many tanks, that means placing them close to the bottom and towards the corners or in shaded areas. Consider elevating your sun corals on live rock if you keep any animals like engineer or other gobies likely to create a sandstorm that might bury your precious sun corals.
Sun corals don’t have any particularly distinct needs, in terms of ideal water parameters. So the standard water parameters are appropriate. You can find out more about those water parameters here.
Sun corals are masters at capturing prey. They will greedily accept mysis shrimp, brine shrimp, copepods, rotifers as well as meaty foods like pieces of clam, chopped fish or other seafood (scallops, shrimp, etc.). The key is to have the food chopped up into small enough pieces.
Unless you have a tank full of other non-photosynthetic corals, you will want to target-feed your sun corals, which essentially means using a turkey baster or Julian’s thing to direct an underwater puff of food at the open feeding polyps.
Which brings up another important point–many people report that sun corals’ preferred time to eat is after lights out. Over time, you can coax them out earlier, but warned that the sun coral may extend your bedtime (depending on when you have lights out.
You could feed your sun corals small amounts of food as often as you like, but if you’re looking for a recommendation–start with feeding them 2-3 times a week. Assess whether they are happy and growing with that frequency. If you have the time and are willing to devote it to feeding your corals, you could increase the frequency up to ~ daily, but this is not a requirement.
You can coax a ‘sleeping’ sun coral into feeding mode by priming the process with an initial small burst of food directed at the closed polyps. You can then wait a few minutes and the feeding polyps should extend. After that, you may feed when ready.
With a little time, patience and moderate aquarium skills, these beautiful corals are a great addition to a mature tank. The keys are consistent feeding, sufficient calcium levels and giving them enough room to grow.
Your turn—have you kept the sun coral? What has your experience with them been? Please leave a comment below.