lighting

Dear Smokey:

I’m not familiar with Smart Lights so I can’t comment on how suitable they would be for your corals and marine plants or macroalgae.

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. However, I can tell you that metal halides are often used to display seahorses at public aquaria and zoos. For example, the 2002 Seahorse Husbandry Manual indicates that Hippocampus erectus are commonly kept under metal halide lighting. Brian Zimmerman and Heather Hall maintain a very successful breeding program for H. capensis at the London Zoo, with the main tank being illuminated for 11 hours a day by 2 HQI metal halides (150 watts each, 10,000 Kelvin). Karen Brittain also kept H. fisheri at Waikiki Aquarium under metal halide lighting with a natural photoperiod. Likewise, Jorge Gomezjurado reports that he has kept adult H. ingens and H. reidi on display at the National Aquarium in Baltimore under Metal Halides Lamps (175W 6500K) that provided a photoperiod of 12:12 L:D without any problems.

So metal halides would be considered overkill by most seahorse keepers, and not my first choice, but the pros often use them and I know many reef keepers who keep seahorses in their systems under metal halides. Often the reefers will keep the coral and inverts that require strong light at one end of the tank, where the metal halides are concentrated, and keep the other of the tank shaded to accommodate the seahorses, reserved for coral that don’t need high-intensity lights. There’s no reason you couldn’t do the same thing…

Basically, you can’t go wrong with seahorses when it comes to lighting as long as you provide some dimly lit areas they can retreat to when they would like to get away from the light and some brightly lit areas they can move to when then want to bask in the light. A good way to create the low light zones is to position sections of aluminum foil under your reflector or hood to provide shaded areas below wherever you want them.

Personally, I like to provide my 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. 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 seahorse 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.

All things considered, I would be more concerned about using a breeder tank for seahorses than your lighting. Breeder tanks tend to be long but fairly shallow, whereas the greater seahorses do best in tanks that are 20 inches tall or higher. They are susceptible to depth-related conditions such as gas bubble disease and need the vertical swimming space in order to mate. As you know, the female deposits her eggs in the male’s brood pouch during the copulatory rise, which often takes them near the surface of the aquarium, and if the tank is too shallow, it can make it difficult for them to breed successfully. How tall is your if 40-gallon breeder tank?

Best of luck with your new seahorse setup, Smokey!

Happy Trails!
Pete Giwojna