what types of corals do I use?

Dear Seagazer:

I’m not Leslie, but I thought I’d chime in about the lighting you need, if you don’t mind. If you look up my previous post (my reply to your "Scared!" message), you’ll find a list of seahorse-safe corals that generally do well under moderate lighting and moderate water movement. You certainly don’t need expensive metal halide lighting for any of the corals on that list. In fact, I find power compact lightning works well for both seahorses and the type of soft corals you are considering, as discussed below.

The type of lighting (bulbs or tubes) you use doesn’t matter too much for seahorses — they will be happy as long as you provide them with some shaded areas where they can get out of the light as well as some well-lit areas where they can bask in the light as they see fit (seahorses like to encourage algae to grow on their bodies as a form of natural camouflage). Zoos and large public aquaria often display seahorses under metal halide lighting (Bull & Mitchell, 2002) whereas hobbyists often use the standard fluorescent tubes that came with their aquarium hood or reflector. For example, at the National Aquarium in Baltimore, adult Hippocampus reidi and H. ingens are displayed either under cool-light fluorescent fixtures that maintain 500-800 Lux or under Metal Halides Lamps at 175W 6500K (Bull & Mitchell, 2002). Both work equally well. For the average home aquarium, metal halides are a bit too expensive, provide far more output than seahorses require, and generate a lot of heat, so various actinic and fluorescent bulbs often work better for the home hobbyist instead. But in my opinion, providing your seahorses with a proper photoperiod, including a dusk and dawn of sorts, is more important than the types of bulbs you use. Here’s an excerpt from my new book (Complete Guide to Greater Seahorses) that discusses the lighting requirements for seahorses in the photoperiod that I prefer in greater detail:

Aquarium Lighting:

Seahorses do not have any special lighting requirements other than the fact that most species prefer low to moderate light levels rather than excessively bright light. Because of this, lighting is another area most seahorse keepers neglect to the detriment of their herd.

In the wild, seahorses are most active in the early morning hours, conducting their courtship displays, daily greetings, and mating rituals during these relatively low-light "twilight zones" (Vincent, 1990). They have a corrugated retina especially rich in rods, which gives them excellent visual acuity under twilight conditions and low light levels in general.

With this in mind, I believe it is important for hobbyists to provide their seahorses with a natural day/night period that includes twilight periods at "sunrise" and "sunset."

To accomplish this, I like the power compact (PC) light fixtures that include two tubes — one actinic and one daylight fluorescent — with dual ballasts so that each ballast can be placed on a separate automatic timer. I like to have the bluish actinic come on before the daylight tubes and stay on after the daylights go off, thereby providing a simulated dusk and dawn. This is important for seahorses since they conduct most of their courting and breeding in the early morning hours under twilight conditions. It’s a neat effect and fish and invertebrates can then anticipate "lights out" rather than being plunged into total darkness at night or suddenly thrust into bright light in the morning (Giwojna, 2005). I also adjust the timers to lengthen or shorten the daylight periods in accordance with the changing seasons. (All my thanks to Jennifer Myerscough for recommending this lighting system to me – it’s working out splendidly!) I find that maintaining a natural cycle this way aids reproduction.

In short, I find PC lighting to be a good compromise for a SHOWLR system. Power compacts provide plenty of light for macroalgae or the seahorse-safe soft corals in a modified reef system without being too bright, and the dual ballast system allows for a natural day/night rhythm that changes with the seasons. The resulting dusk and dawn facilitate courtship and help the seahorses maintain a natural reproductive cycle. [end quote]

So those of some of the things to keep in mind when selecting the lighting for your seahorses, Seagazer. For all extents and purposes, you really can’t go wrong no matter what bulbs you chose as long as you provide both shaded areas where your seahorses can escape from light altogether and well-lit areas where they can bathe in bright light as they please. You will find your seahorses will move into and out of the light often, seeking the comfort level that suits them at the moment.

Optimum water quality, inadequate water movement, and appropriate lighting are the keys to keeping corals healthy in the aquarium. If your tank is still relatively new, you may want to let it stabilize and mature a bit longer before you add too many corals. At some point when they are breaking in, most aquariums go through a phase where diatoms or nuisance algae blooms, and you want to make sure your new tank is well established and has settled into a state of equilibrium before you start introducing corals.

Best of luck with your seahorse setup, Seagazer!

Happy Trails!
Pete Giwojna