Sunburst low light question

Dear D:

Yes, one reason brightly colored seahorses may darken in a new aquarium is if the lighting is too intense. In nature, bright light means exposure to harmful ultraviolet radiation, and the seahorses respond by producing excess melanin, just as people will develop a dark tan in the summertime if they spend a lot of time in the sun. For this reason, seahorses that are displayed under metal halide lighting or other high intensity lighting may darken in coloration due to the excessive production of melanin. As Jorge Gomezjurado (Head Curator at the National Aquarium in Baltimore and the owner-operator of the Draco Marine aquaculture facility) reports, “I have exposed yellow seahorses to strong metal halide and they have turned black in few hours.” It would be a terrible shame to display colorful seahorses such as Sunbursts or Fire Reds or Pintos under metal halides or other high-intensity lighting, only to see them darken in coloration and lose their vivid colors…

On the other hand, the proper lighting can often greatly enhance the appearance of colorful seahorses. As one example of how this can work, Grolux fluorescent lighting stimulates dazzling coloration in bright red or orange seahorses (e.g., Mustangs or Sunbursts in their red or orange color phases, the bright red orange color morphs of H. reidi, or perhaps H. barbouri with vivid orange coloration). Osram Gro-lux fluorescent bulbs put out wavelengths of light that are concentrated toward the red and violet regions of the spectrum. They are intended to stimulate better plant growth, but have the added effect of greatly enhancing any red or orange or purple colors they illuminate. When bathed in Gro-lux light, bright red or orange seahorses literally glow!

In fact, when I first discovered this effect — with a Red Philippine Lobster (Enoplometapus sp.) in a specialty tank — I believed I was witnessing actual fluorescence. The seven-inch bulldozer of a crustacean was covered with sensory bristles that made it look almost fuzzy, and under the Gro-lux bulb, the extraordinary excavator was instantly suffused with a fiery radiance that dazzled the eye. At first I thought its exoskeleton was glowing, and I hypothesized that perhaps the chitin was infused with the type of calcite crystals that fluoresce under ultraviolet, and which perhaps could be similarly excited by the wavelengths emitted by the Gro-lux bulb.

I only realized the truth when I added the same type of bulb to an aquarium containing, among other choice specimens, a gorgeous purple-and-yellow Royal Gramma and a rare red-orange Hippocampus erectus. Now, that seahorse was very colorful under any kind of lighting, but as soon as that Gro-lux lamp switched on, the erectus was ablaze with a shade of brilliant Day-Glo orange ordinarily only seen from neon signs, nuclear meltdowns, and psychedelic posters displayed under UV. The stunning steed shone with a luminous aura, awash with glorious orange glow that made it look like it was swathed with liquid fire. Suddenly, it was the color of red-hot lava, aflame with a blinding orange incandescent, and the result was truly spectacular. Then my shy Royal Gramma emerged from its sleeping cave to keep the seahorse company, and its magenta end was immediately suffused with a dazzling hot-pinkish purple glow that ended abruptly where its yellow half began. That made it obvious that the new bulb was accenting colors at the red and violet regions of the spectrum, which are precisely the wavelengths of light chlorophyll absorbs best.

The reflected Gro-lux light was responsible for the breathtakingly beautiful effect, and it will produce the same scintillating display in your aquariums. It would certainly set red and orange Brazileros (Hippocampus reidi) aglow, as well as Mustangs or Sunbursts (H. erectus) in their red to orange color phases. Pink to purple seahorses should be similarly enhanced under Gro-lux lighting. Fire Reds that approach true scarlet or crimson would no doubt blaze brilliantly, but I’m less certain what effect it would have on specimens that tend more toward auburn or which display that rich mahogany luster instead. And it would have no effect whatsoever on black or brown or yellow or green seahorses, which would absorb the light rather than reflecting it. Suffice it to say if we’ll be including any red, orange, or purple seahorses in your exhibit, you should use Gro-lux bulbs in order to display them in all their glory!

Otherwise, Paul Groves, curator at Underwater World in Perth, recommends combining a triphosphor (6500k) fluorescent tube with a Phillips TL Blue fluorescent tube to produce the best overall lighting and colors for a seahorse exhibit. After much experimentation, he found the above combination of lights really encouraged the coloration of the seahorses as well as being aesthetically pleasing to the eye. He reports that the diversity in colors displayed by Hippocampus subelongatus was much less under any other lighting. So if you want to accent the colors of red, orange, or purple seahorses, Osram Gro-lux fluorescents are ideal; on the other hand, bright yellow seahorses display best under ordinary white (daylight) florescent light, and for other seahorses, try a 6500k triphosphor fluorescent in conjunction with a Phillips TL Blue fluorescent to keep them looking their best. And avoid metal halide lighting for your seahorse exhibit.

In your case, D, if your light fixture is adjustable, I would tone down the “cool” end of the visible spectrum (i.e., blue/violet) and turn up the “warm” end of the visible spectrum (i.e., yellow/red) in order to accentuate the coloration of bright yellow or orange seahorses. As for the overall light level, the settings that are appropriate for live gorgonians, tree sponges, and colorful macroalgae will suit seahorses perfectly as well.

If you contact me off list ([email protected]), I will be happy to send you some more suggestions for keeping your ponies looking their best and brightest at all times.

Best wishes with all your fishes, D!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support

Dear Jim:

Yes, sir – if the lighting was the primary reason that the seahorses’ darkened in coloration, then adjusting the lighting may well be sufficient to cause the seahorses to brighten in coloration again.

For example, here is a copy of an e-mail I received from a hobbyist just a few days ago in which she mentions that very phenomenon:

‹open quote›
To: Pete Giwojna <[email protected]>
Sent: Mon, Jun 28, 2021 4:57 pm
Subject: RE: Ocean Rider seahorses…

I figured out why he turned silver after reading your article. I have been doing a lot of rearranging in the seahorse room for the last couple of weeks. Because of this I have had the ‹bright› white LED ceiling light on… It ‹never› occurred to me they would change that much just on a ceiling light. I should know better.

Thank you,
Cheryl
‹close quote›

However, Jim, there are any number of environmental conditions that can also affect the coloration of seahorses, often by affecting the ability of chromatophores to contract and expand, and these must also be addressed for best results. These include the following factors:

Stress — seahorses often respond to stress by darkening.

Emotional state — when excited, seahorses typically brighten in coloration, reflecting a state of high arousal. On the other hand, fear, anxiety and distress are generally accompanied by dark, somber hues.

Social interactions — seahorses often brighten during their courtship displays; pair-bonded seahorses likewise brighten during their morning greeting rituals, and rivals go through characteristic color changes (see below) during their confrontations and competitions.

Competition for mates — dominant individuals brighten; subordinate seahorses darken in submission.

Hormonal influences — juvenile seahorses may change coloration when they hit sexual maturity in response to a change in their hormonal levels.

Poor water quality — high levels of nitrogenous wastes (e.g., ammonia, nitrite or nitrate) can cause chromatophores to contract and colors to fade.

O2/CO2 — low oxygen levels (or high CO2 levels) can cause colorful seahorses to fade and they will blanch when subjected to hypoxic conditions.

Background colors — seahorses will often change color in order to blend in with their immediate surroundings.

Medications — some antibiotics and malachite-green-based remedies negatively affect color.

Tankmates — seahorses may change their base coloration to blend in with the rest of the herd or to match their mate (or a potential partner). This can work both ways: a dark seahorse may brighten up and assume vivid hues when introduced to an aquarium with bright yellow or orange tankmates, just as a brightly colored seahorse may darken and adopt subdued coloration when placed amidst drab tankmates. Of course, seahorses are not responding to peer pressure when they conform in this manner; rather, this is probably instinctive behavior. In nature, it’s not healthy to be too conspicuous and stick out in a crowd since an individual that stands out from the rest of the herd draws the attention of potential predators to itself.

Temperature — chromatophores tend to contract at high temperatures (above the seahorse’s comfort zone), causing colors to fade; cooler temps within their optimal range can make pigment cells expand, keeping colors bright.

Disease — skin infections (bacterial, fungal, or parasitic) can cause localized loss of pigmentation or discoloration of the affected areas.

Diet — seahorses cannot synthesize the pigments used in their chromatophores. It is therefore important to enrich their food with pigments such as carotenoids in a form that’s easy for them to absorb. If color additives are not provided, the chromatophores will gradually lose their pigments and the seahorse’s color can fade. Vibrance, for example, is exceptionally rich in Vitamins A and C as well as natural carotenoids, which are not found in Mysis relicta. This is important because the carotenoids are a class of yellow to red pigments, which include the carotenes and the xanthophylls. Like all cells, individual pigment cells have a limited life expectancy in the body and must be regularly renewed. Marine organisms cannot synthesize carotenoids, so if they do receive adequate amounts in their diet, they will have difficulty replenishing their red and yellow pigments. This means that the colors of bright yellow, orange, and red seahorses will gradually fade over time if their daily diet is lacking in carotenoids. So don’t neglect the enrichment step in your daily feeding regimen! If seahorses are fed a strict diet of Mysis relicta without additional enrichment, they may begin to develop dietary deficiencies over time, and both their health and coloration will eventually suffer.

Lighting — seahorses may darken in response to UV radiation or intense lighting (e.g., metal halides) as a protective measure, whereas bulbs that emit wavelengths of light shifted towards the red end of the visual spectrum (i.e., Grolux fluorescent tubes) can greatly enhance the coloration of red, orange or purplish seahorses to the point that they almost literally glow.

In short, you can expect your seahorses to exhibit a number of different color phases over the coming months and years. Expect them to display brighter colors when they get serious about breeding and courtship, for instance. And if they happen to adopt a colorful hitching post as their favorite perch or hang out, they may gradually change coloration to match their favorite resting spot.

All of the different factors mentioned above need to be addressed in order to keep your seahorses looking their best and brightest, Jim. There are a number of other things beside the lighting and colorful perches for your seahorses that you can explore to influence their coloration and encourage them to display bright colors. These are discussed in some detail in a two-part article on coloration in seahorses that I recently wrote for Conscientious Aquarist online magazine. The first article explains how seahorses use their amazing color changing ability, while the second article explains how they accomplish their color changes and is loaded with tips for keeping colorful seahorses such as Sunbursts looking their best and brightest. You can read the articles at the following URL’s and enjoy Leslie Leddo’s magnificent photographs. Just copy the following URL’s and paste them into your web browser, and it will take you directly to the articles:

part one:
http://www.wetwebmedia.com/ca/volume_4/V4I1/hippocampus_color/Color_In_Hippocampus.htm

part two:
http://www.wetwebmedia.com/ca/volume_4/V4I2/hippocampus_color2/Color_In_Hippocampus2.htm

One of the suggestions in part two is to choose colorful pieces when aquascaping the seahorse tank and furnishing them with hitching posts, and I have a couple of tips in that regard that may also be useful, Jim:

For example, if you will be keeping live rock in the aquarium with your seahorses, try to select colorful pieces that are overgrown with coralline algae in order to encourage your seahorses to display brighter colors, as explained in more detail below.

The best way to obtain live rock is from an aquarium store in your area that caters to reef keepers. They will have pre-cured live rock available and you can handpick interesting rock formations that are heavily encrusted with pinkish-purple coralline algae for your aquarium. That will also save you the cost of having the live rock shipped to you, which can be considerable because of the weight of the rocks.

Seahorse keepers who want brightly colored seahorses will often choose to confine the live rock to their aquarium sump or refugium, rather than the main tank, particularly if they are unable to obtain colorful live rock with lots of coralline algae. The reason for this is that an aquarium with lots of ordinary brownish live rock can sometimes have an adverse effect on the appearance of ponies with vivid coloration. As we all know, our seagoing stallions will often change coloration in order to better blend in with their background, and that means that they may occasionally adopt earth tones in an aquarium that is dominated by drab live rock. Although that’s not a concern with dark colored seahorses, it would be a shame to purchase a bright yellow or orange or red seahorse only to have it assume a brown or beige or sandy or grayish background coloration that matches the live rock. Placing the live rock in the sump or refugium instead of the display tank eliminates this possibility, yet still allows the aquarium to benefit from the greater stability, enhanced biological filtration, and denitrification ability (which helps keep nitrates nice and low) provided by the live rock.

When it comes to hitching posts and decorations, seahorses in general tend to prefer perches that are bigger in diameter over skinnier ones that are a bit more difficult to get a good grip on with their tails, but other than that, it’s very difficult to predict what they’ll go for. I have noticed that tree sponges and tube sponges — both the real thing (which are difficult to keep healthy) and the lifelike artificial versions — almost always seem to be particular favorites. Very often such sponges are bright red or yellow or brilliant orange in coloration, but I think it is the structure and texture of the sponges that attracts the seahorses more than the color.

Tree sponges in particular are veritable seahorse magnets and the ponies really do love them. They are usually brightly colored (red and orange shades are common) and their shape and texture seem to make them irresistible to seahorses as hitching posts. Very often, all the seahorses in the tank can be found clinging to the same tree sponge together, eschewing other nearby holdfasts that appear every bit as comfy and attractive to human eyes.

An artificial colorful tree sponge or two may be an excellent way to stimulate color changes in your seahorses. Collectors will often find bright red or vivid orange seahorses living in beds of colorful sponges in the wild. Leslie Leddo has some great photos of a bright orange H. barbouri and an orange Pinto perched on a red-orange tree sponge in her aquarium, and the seahorses blend in perfectly with their bright orange hitching post.

Pay special attention to the hitching posts you select for your seahorse tank. Strive for bright reds, oranges, and yellows — even shades of pink or purple — in anything your seahorses may adopt as a holdfast. These aquatic equines — especially the stallions — will often choose one particular hitching post as their home base and spend much of their time perched right there (think of your Dad hunkered down in his favorite easy chair in the den). Once they adopt a favorite base of operations like this, they will sometimes proceed to change coloration to match their preferred resting spot. So you want to encourage them to adopt one of the more vivid pieces as a favorite holdfast.

Mildred Bellomy provides a perfect example of how this works in the Encyclopedia of Seahorses:

<Open quote>
Elizabeth Goetz of Miami, Florida has kept one or more seahorse stables in her home for many years. She wrote the following anecdote about one of her seahorses that “turned red with envy.”

“About five or six years ago, it was just about this time of year, [Christmas], we began our holiday decorating. Our own is not the simplest place to decorate for special occasions in that we have so many aquariums — approximately 35 at the time. Fourteen of these tanks were the homes of seahorses (Hippocampus hudsonius). [Editor’s note: Hippocampus hudsonius is an outdated synonym for Hippocampus erectus.]

“After completing the superficial home decorating, we decided it would be a grand idea to really go all-out with the holiday scheme and include the aquariums. On checking through our collection of assorted Christmas bric-a-brac, we found a number of ceramic items suitable for display in sea water. There were Christmas trees in north-woods green, gaily ornamental angels lovely enough to have stepped from the very gates of Heaven, winged carolers, haloed mermaids, etc., and lo and behold! — one, red-robed, sitting Santa Claus, with the most adorable facial expression one could imagine. Here, then, was ample material to decorate to one’s heart’s content.

“The walls of the dining room are lined with 10- and 15-gallon aquariums so we chose the most prominent 15-gallon tank for this pixie-like Santa. This was the home of five seahorses and they, too, seemed really happy with the decorating idea. We will not argue the point that any other smooth ceramic piece would have pleased them equally, but it is more satisfying to believe that the seahorses joined in with the holiday spirit. Nevertheless, almost as soon as their former hitching posts were removed and a Christmas item put in its place, the seahorses wrapped their respective tails around the new items and were completely at home again. Though scientists may adamantly disagree, we firmly believe fish do have varied personalities, even within their own species. Ask any hobbyist. We have had friendly seahorses, unfriendly ones, and downright cussed critters; the timid, placid, bold, and boisterous, and all of these and more personality traits were observed in H. hudsonius alone.

“All of the foregoing is merely to set the stage for our tale of the seahorse that turned red with envy.

“Our little seahorse star of this story was the most calm and timid of the five in our Santa aquarium. He would cruise calmly from his hitching post for exercise and return to his own station a short distance from the Santa, never trying to usurp the throne of another of his tankmates. The others did claim Santa as a resting place. Seldom was the time when Santa didn’t have the tail of a seahorse wrapped gently around an arm that rested on his pack, or around the tipped-up tassel of his toboggan. Our calm but “envious one” would stare in Santa’s direction almost constantly, while resting. It might be well, at this point, to emphasize that Santa was the only red-colored object or part of this aquarium. This previously dark (brownish) seahorse — originally colored the same as the other four — turned bright red. His change occurred gradually, over a period of about a week and it is quite true, he became a most beautiful red for the holidays.”

Now we are well aware of color changes in nature, assumedly for protective measures, and being mindful of the fact that this timid little fellow did not cling to red-robed Santa, but remained some distance away, what then could the whimsical-minded, season-inspired person presume other than that the most peace-loving seahorse in the aquarium bathed himself in the reflected glory of the mythical man-of-the-hour, the one and only Santa Claus. <Close quote>

Notice that the seahorse reverted to its usual dark brown coloration when the scarlet-clad Claus figurine was removed from the aquarium after the holidays.

The moral of this story is that you can never tell what might catch your seahorse’s eye and trigger a corresponding color change in response to a change in its immediate environment. With that in mind, some hobbyists have experimented with brightly colored aquarium backgrounds and achieved surprising results. For instance, I have received reports that a bright orange aquarium backing can stimulate vivid color changes in some seahorses, although the result is often not what you would expect. (One wonders if Hippocampus perceives all colors the same way we do.) Don’t hesitate to experiment until you find the right combination that works well for both you and your seahorses.

Transitory color changes can be achieved rapidly, in a matter of moments, but long lasting transformations occur gradually, and may take days to complete. This is often the case when a seahorse adopts a favorite hitching post and makes it his home base or center of operations. When that happens, the seahorse will often assume a color that closely matches its chosen resting spot so it blends in with its background when hanging out at headquarters. This is akin to the situation with the ceramic Santa; the color matching occurs slowly and, once the transformation is complete, the seahorse intends to keep its new coloration indefinitely.

Seahorses often tend to gravitate towards gorgonians as well, and the big purple gorgonians that are large in diameter are also usually very popular with seahorses. Otherwise, they seem to like genuine corals and synthetic corals about equally well, and the brightly colored formations (orange, red, or vivid yellow) usually produce better results than plain white corals.

Hitching posts for your seahorses can thus be either live or artificial marine sea grasses, algae and corals. If you decide to try an assortment of colorful artificial corals, seahorses often prefer red or orange pieces. Many hobbyists report good results using artificial sponges, gorgonia, staghorn coral, octopus coral and pillar coral in the appropriate colors to keep their seahorses looking their brightest. They look entirely natural and lifelike, with lots of branching projections that make great hitching posts for seahorses.

Best of luck encouraging your ponies to look their best and brightest at all times, Jim!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support