Seagrass tank

(long page-click to view in large frame)

The seagrass tank was originally set up as a place to grow turtle grass and various marine algae free from fish herbivores. It is also a place where a variety of small invertebrates can proliferate nearly free from fish predation, and where a number of different sorts of sponges can grow away from the blue Linkia seastar that would eat them in the reef tank. The only fish currently in the tank is a large male bicolor blenny that lives in the front bulkhead connecting the two tanks.

If you visit the aquaria in person, get up close to the glass and look very closely at this tank, especially in the nooks and crannies under corals and rocks. You will see that this tank is teeming with life, including an abundance of tiny fast-swimming mysid shrimp (often mistaken as fish fry by visitors), amphipods, ostracods, fireworms, flatworms, medusa worms, small brittlestars, chitons, and other small or tiny invertebrates.

This tank has also become a place where numerous cuttings of gorgonians and stony corals from the reef tank have been placed. Many of the stony coral cuttings are developing into fine colonies sitting unattached on the sand.

The tank also has an abundance of mushroom anemones, colorful zooanthids, and pulsing Xenia soft corals, the latter being found in large patches on the glass (right side of tank), on the rocks, and attached to the macroalgae and turtlegrass blades.

Anemone is gone:

If you compare this photo to older photos, you will notice a formerly prominent resident is missing. The large purple long-tentacled anemone that formerly hosted the clownfish died after we had had it for over a year. The cause of the death is unknown, but we suspect that improper water flow patterns in the tank might have contributed to its decline. Unfortunately, this is the fate of most clownfish-hosting anemones in captivity. Most of the clownfish-hosting anemone species are extremely demanding organisms to keep, and are better left in the wild. However, one species (the bubble-tip anemone, Entacmea quadricolor), has a better track record, often even reproducing through division in home reef aquaria. We plan to try setting up a clownfish-anemone mutualism display again in the future, using a captive-propagated specimen of this hardier species the next time.

The clownfish, by the way, are now residents of the reef tank, where they have been spawning every few weeks since Spring 2000. Though clownfish are always found with host anemones in the wild, they do perfectly well in captivity without them. In clownfish, the instinctual urge to associate with an anemone is strong, however, and sometimes captive clownfish lacking an anemone will adopt other sessile invertebrates as surrogate hosts. Our pair, for example, spends nearly all of its time among the long polyps of a large Xenia elongata soft coral colony on the right side of the reef tank.