weird colors

Dear FERS4REEF:

Yes, sir, seahorses can grow and shed fleshy extensions of their skin known as dermal cirri. These extravagant appendages are a variable trait and are seen most commonly in juvenile seahorses living in a weedy environment, such as floating rafts of Sargasso seaweed. The cirri are normally the same color as the rest of the seahorse’s body.

Dermal cirri are fleshy tabs or branching outgrowths of the skin that serve to break up the seahorse’s outline and allow it blend into its weedy habitat all the better, a sort of natural camouflage. Unlike spines, cirri are not permanent structures in most cases. Up to a certain age at least, seahorses appear to be capable of growing or shedding these fleshy filaments as the occasion demands in order to better suit their surroundings. For example, specimens that are rafting in clumps of Sargassum are apt to have well-developed cirri, giving them an appropriately shaggy appearance, while a seahorse inhabiting the mudflats of an estuary will be smooth skinned. Cirri grow most commonly on the head and neck region and are more common in juveniles than adults.

The presence of cirri is a highly variable trait and some species never have them. They are very rare or nonexistent in many seahorses, while in other species they are relatively common. For example, Hippocampus comes and H. reidi are smooth-bodied seahorses that almost never seem to develop cirri (Giwojna, Oct. 2003). Consider them cue balls — the Kojaks of seahorses. On the other hand, Hippocampus guttulatus are famous for their cirri and many Pot-Bellies (H. abdominalis/H. bleekeri) also sport fancy headdresses (Giwojna, Oct. 2003).

But even in seahorses where cirri are not uncommon, such as Hippocampus zosterae and H. erectus, the occurrence of cirri varies greatly from individual to individual (Giwojna, Oct. 2003). Most dwarf seahorses have no cirri, but some of them are regular little fuzz balls. That’s the case with Hippocampus erectus as well. Most Lined Seahorses (H. erectus) lack these appendages altogether, some have just a few, and the individuals with really extravagant cirri are relatively rare (Giwojna, Oct. 2003).

It’s a shame seahorses with well-developed cirri aren’t more commonplace because they can be quite breathtaking. A heavy growth of cirri can transform an ordinary specimen into a real show horse, making them appear as if they were adorned with a fancy mane or wearing an Indian war bonnet. A seahorse with extravagant, well-developed cirri can indeed be very exotic looking, but sometimes it has the opposite effect, lending them a comical appearance instead (Giwojna, Oct. 2003). I’ve seen shaggy specimens that looked like they were having a bad hair day, sporting a Mohawk or spike hairdo (Giwojna, Oct. 2003). Voila — a punk-rock pony, going through its rebellious teenage phase! Either way, they dress up the seahorses and give them a little extra pizzazz, and that’s what makes seahorse keeping so much fun!

Since Hippocampus reidi rarely ever develop cirri, I don’t think you’re going to see your specimen with the dark purplish stripe develop a lot of fancy fronds or exotic appendages, sir. But it is quite possible that your H. reidi may change its coloration in order to better match that of its H. kuda 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. Your H. reidi may even have its eye on one of the kuda as a potential mate!

For a complete discussion of how and why seahorses change color, please check out the a two-part article on coloration in seahorses that I recently wrote for Conscientious Aquarist online magazine. You can read the articles at the following URL’s and enjoy Leslie Leddo’s magnificent photographs:

part one:
<http://www.wetwebmedia.com/ca/volume_4/V4I1/hippocampus_color/Color_In_Hippocampus.htm&gt;

part two:

<http://www.wetwebmedia.com/ca/volume_4/V4I2/hippocampus_color2/Color_In_Hippocampus2.htm&gt;

Best of luck with your seahorses, FERS4REEF! Here’s hoping your reidi completes the transformation into a beautiful purplish seahorse!

Happy Trails!
Pete Giwojna