Dear corallife:
If you will be relying on the live rock to control nitrates levels via denitrification, and to provide the bulk of the biofiltration via dentrification, then I would recommend 1-2 pounds of live rock per gallon of water in the aquarium for best results. For example, under those circumstances, a 30 gallon aquarium would need at least 30 pounds of live rock and no more than 60 pounds of live rock to do the job.
Yes, it is true that seahorses prefer relatively low light levels. High-intensity lighting such as metal halides would be overkill on the average seahorse tank and should probably be avoided anyway due to its tendency to cause overheating. This doesn’t necessarily mean that the seahorses will shun bright light, but rather that you should be sure to provide plenty of well-shaded areas where they can get out of the light when they wedge as well as well-lit areas. Seahorses will, however, be uncomfortable in excessively bright light, which may cause them to go into hiding in order to escape the light. And another thing to bear in mind is that lighting that is too intense can cause seahorses to produce excess melanin and darken as a protective mechanism to guard against UV light they associate with bright light. So if you have colorful seahorses, it’s best to avoid metal halide lighting, and high-intensity lighting in general, in order to keep their seahorses looking their best and brightest.
If you’ll just be keeping seahorses and macroalgae in your seahorse tank, then standard fluorescent bulbs are all that you should need. If you’ll be keeping seahorse-safe corals as well as the ponies, then I find that compact lighting works very well, as discussed below:
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before the daylight tubes and stay on after the daylights go off, thereby providing a simulated dusk and dawn (Giwojna, unpublished text). 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. I find that maintaining a natural cycle this way aids reproduction (Giwojna, unpublished text).
Basically, 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 or generating too much heat, 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 (Giwojna, unpublished text).
For all intents and purposes, you really can’t go wrong no matter what lighting system you chose as long as you avoid excessively bright light and 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.
Best of luck with your seahorses, corallife!
Happy Trails!
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
