Here is another marine creature that first year marine science students can identify right away but when asked which phylum and which class it belong – there is another long pause.

We all know and love seahorses – they are iconic.  But what type of animal is a seahorse?  Some know, but many would be surprised to find that it is a fish.  They certainly do not look like fish.  They lack scales as we know them, they are not “torpedo-shaped” (fusiform), and the fins are not noticeable.  Like most – I know it is a seahorse but not sure after that… it’s just a seahorse.

Yes, it is a fish.  The general characteristics of fish would include having a backbone (seahorses do), body covered with scales (we will discuss this more in a second), they possess gills (yep), and they have fins (they have some).  There are over 500 species of fish from the Gulf, and you begin to divide them into families based on the following characteristics – we will follow those for the seahorse…

They lack ventral fins – many fish do, but seahorses do not have these.

Body is elongated but not flattened laterally, true for seahorses.

Gill openings restricted to the side of the body, true for seahorses.

Snout is tubular and body covered with bony plates (this is where the scale thing comes in – seahorses have fused scales that form armor like plates).

If you are a fish with these characteristics, you are in the fish family called Syngnathidae.

The synganthids include the pipefish and the seahorses.  Pipefish look MORE like fish.  Their head and body are continuous and in a straight line – like fish are supposed to be – unlike the head and body being at 90° angle, which you find in seahorses.

In the northern Gulf there are seven species of pipefish and two species of seahorses.  They inhabit areas with vegetation – our seagrass beds, feed on plankton, and – as many people do know – the males carry the eggs.  They do require systems with higher salinities.  St. Joe Bay has higher salinity than Santa Rosa Sound or Big Lagoon – thus support a larger population – but we do have seahorses in lower Pensacola Bay.

The technical difference between the two species of local seahorses are the number of rays in their dorsal and pectoral fins.  But for most of us it is their size.  The Lined seahorse averages about five inches in length.  The Dwarf seahorse only reaches 1.5 inches.

So… the famous seahorse is a type of fish.  Many people did not think that…

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