Lighting & Protein Skimmer

Dear Dodge:

Yes, sir — standard incandescent or fluorescent bulbs are quite adequate for seahorses. When it comes to lighting, seahorses do not have any special requirements other than the fact that most species prefer low to moderate light levels rather than excessively bright light. They have a corrugated retina especially rich in rods, which gives them excellent visual acuity under twilight conditions and low light levels in general. Some species are even believed to be nocturnal (e.g., Hippocampus comes and H. ingens) and have no trouble seeing and feeding at night. Seahorses will do just fine under ambient room light with no aquarium light fixture whatsoever, although hobbyists prefer to keep their tanks illuminated for aesthetic purposes and so they can view them better.

So either an ordinary incandescent bulb or standard fluorescent tube is great. Between the two, I would strongly favor a fluorescent light fixture because they give off less heat (overheating and heat stress can become problems for seahorses during summertime heat waves) and because the fluorescents are more economical to operate. Easier on the old electric bill.

For all intents and purposes, you really can’t go wrong no matter what lighting system 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 the 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.

With regard to a protein skimmer, even if you limit your aquascaping to artificial plants and synthetic corals sculptures, foam fractionation will still be effective and appropriate for a seahorse tank. Our galloping gourmets have hearty appetites and are anything but dainty eaters. Their digestive tract is short and fecal production is rapid. I can assure you they will produce plenty of organic wastes to keep a protein skimmer busy.

Although seahorses can certainly be kept successfully without the use of a protein skimmer, I recommend including a good skimmer for best results. As a rule, seahorses are messy feeders, particularly when scarfing down enriched frozen Mysis. Ample evidence of this is revealed every time they scarf one up. As they snick up a shrimp with their slurp-gun snouts, water is passed over their gills and expelled forcibly (it is this very process that generates the powerful suction they use to slurp up their prey). As the jet of water is ejected through their gills, it carries a cloud of macerated particles and debris with it. It is a startling sight the first time you observe this phenomenon, for it brings a fire-breathing dragon to mind. As one young hobbyist matter-of-factly described it, "My seahorse blows smoke out of its ears when he eats." I’ll be darned if that’s not exactly what it looks like, too!

The majority of the undesirable metabolites, organic wastes and excess nutrients that accumulate in our aquariums and degrade water quality are "surface-active," meaning they are attracted to and collect near the surface of a gas-liquid interface (Fenner, 2003). Skimmers take advantage of this fact by using a column of very fine air bubbles mixed with aquarium water to trap dissolved organics and remove them from our systems. This air-water mixture is lighter than the surrounding aquarium and rises up the column of the skimmer until the foam eventually spills into a special collection cup atop the skimmer, which can be removed and emptied as needed. Proteins and other organic molecules, waste products, uneaten food and excess nutrients, and a host of other undesirable compounds stick to the surface of the bubbles and are carried away along with the foam and removed from the aquarium (Fenner, 2003a). As a result of this process, these purification devices are typically known as foam separators, foam fractionators, air-strippers, or simply protein skimmers.

In my experience, nothing improves water quality like a good protein skimmer. They provides many benefits for a seahorse setup, including efficient nutrient export, reducing the effective bioload, and increasing both the Redox potential and dissolved oxygen levels in the water (Fenner, 2003a). They do a tremendous job of removing excess organics from the aquarium, including phenols, albumin, dissolved organic acids, and chromophoric (color causing) compounds (Fenner, 2003a). Their ability to remove dissolved wastes BEFORE they have a chance to break down and degrade water quality makes them indispensable for controlling nuisance algae. A good protein skimmer is an invaluable piece of equipment for keeping your nitrates low and your water quality high when feeding a whole herd of these sloppy eaters in a closed-system aquarium.

When considering the height of the aquarium, taller is better, as a rule. I wouldn’t recommend keeping any of the large breeds of seahorses in an aquarium less than 20 inches tall. Once you get about 20 inches, there are some additional considerations that you must factor into the equation. Certainly an aquarium that is 30-inches tall is better for protecting your seahorses from gas bubble syndrome than a 24-inch aquarium. And if the taller aquarium also has a larger volume, it will provide better stability and a bigger margin for error than the shorter aquarium. But the 30 inch tall aquarium is likely to cost considerably more than a tank that’s 24 inches high, and if purchasing the 30-inch tank depletes your budget to the point where you have to skimp on the filtration, then I would probably prefer a 24-inch tank with superior filtration.

Another consideration is aquarium maintenance. It can be difficult to aquascape a really tall aquarium and perform routine servicing and maintenance on it simply because your arms won’t reach all the way to the bottom. If your tank is so tall that you skip on maintenance and it’s difficult to keep clean, then that may not be best for your seahorses either.

Best of luck finding the perfect aquarium for your needs and interests, Dodge!

Happy Trails!
Pete Giwojna