The secret seahorse

• Description
• Habitat
• Behaviour
• Images

The year 2003 has been a very important one for Pygmy Seahorses. After the description of Hippocampus denise by Sara A. Lourie and John E. Randall, two new species have been seen by divers: one living on soft corals of genus Nephtea sp., photographed in Walea (Togian Islands - East Sulawesi) and another, associated with the hydroid Sertularella sp., seen in Bunaken (Manado - North Sulawesi). I want to talk about this one, because I had the chance to see it and take some photos.

This specie has not yet been described. It seems he was seen for the first time by a local Indonesian guide named Pontoh, so he probably will be named after him and called Hippocampus pontohi. What really is surprising, observing this pygmy seahorse, is his great diversity compared to other species of pygmy seahorses living in those same waters, like Hippocampus bargibanti and Hippocampus denise. These are his main morphological characteristics:

1. He is very small. The few specimens I've seen had a size of about 5-7mm. (without tail). It's possible he is smaller than Hippocampus denise which is now considered the smallest, with an average size of 16 mm.;
2. his body is flat and thin: from a front view he's almost invisible;
3. he's red-orange on his back, with a nearly white belly. Snout is gray-pale blue, while the tail is brown-yellow;
4. he has two typical red spines, with branches, on his back, similar to small wings and one on his head. For this reason he has been informally named the 'Weedy' Seahorse

Unlike his better known 'cousins' H. bargibanti and H. denise, he prefers to live at shallow depths: all of the photographed specimens were at 7 meters (23 feet), on the vertical wall of 'Likuan 2', in Bunaken.

As expected, he is associated with the hydroid Sertularella sp., which grows on short coral branches between small sponges and ascidian colonies. Photos can better describe this habitat, where this seahorse hides and camouflages so well that we needed three dives to find him, even though we already knew where they were living. I want to add that the strong sunlight still present at shallow depths makes them even more difficult to find. So, all the above photos were shot on a night dive.

Bunaken walls are also hit by currents and for this reason this species prefers small recesses or hydroid colonies sheltered by big sponges or other organisms which can offer some kind of protection.

Very little is known about this species. My impression is that he is very active and mobile: he seemingly never stops moving, always jumping and swimming from one hydroid to another. Taking a good photo is very difficult. After the photos I made in June, I came back in November, but unfortunately he had already disappeared. A single specimen had been seen for few days in July, on a dive site called 'Alung Banua', also in Bunaken. But then, he also disappeared. It is very hard to guess what has happened to them. Maybe they moved and hid in different places, or maybe their adult life is short, limited to their reproduction phase. There are no clues to judge by. I only hope he will be soon back again in the beautiful walls of Bunaken! It seems that this species has already been seen before in Wakatobi (South Sulawesi) and in Irian Jaya.