When you search through a rock pool looking for some amazing finds, you might see a quick dash across the pool or out from under a rock. What you’ve probably come across is a rock pool fish. They are notoriously difficult to spot as they dart around the pools very quickly but if you manage to catch one you can find some beautiful species.
Blenny or a goby?
Gobies and blennies are some of the most common species you’ll find in UK rock pools, but it can be hard to tell them apart. One of the easiest ways to identify them is to look at their dorsal fins – if there are two – that’s a goby, but one long one is a blenny. Another way to tell the difference is when lying on the bottom of a rock pool, a goby will have a straight body, whereas a blenny is curved.
Rock goby
If you’ve found yourself a goby with a mottled brown colour, dark bands and a yellow tint on the first dorsal fin, you’ve found a rock goby (Gobius paganellus). These fish can get up to 12cm in length, live up to 10 years and are most common during the summer months.
Shanny
The shanny is a type of blenny also known as the common blenny (Lipophrys pholis). This fish can get up to 15cm in length and are mottled in colour. The best way to distinguish the shanny from other blennies is a lack of visible antennae or tentacles on their head. These clever fish can also survive out of water for a short time during low tide in damp places. Be careful when finding this fish as they can bite! If you want more information on the shanny, you can visit our blog here!
Tompot blenny
The tompot blenny (Parablennius gattorugine) is one of the larger blennies found in UK rock pools which get up to 30cm in length. This fish has more of an orange-brown mottled colour with dark bands along the body. This blenny is most distinguishable by its two-branched tentacles or antennae on top of its head, making it a favourite among underwater photographers.
Montagu’s blenny
A smaller blenny found in rock pools is the Montagu’s blenny (Coryphoblennius galerita) which can grow to 8.5cm in length. This blenny is paler in colour compared to other species with dark greenish bands along the body and blue spots. The Montagu’s blenny has a tentacle on top of its head but only one which is not as branched as the tompot.
Worm pipefish
The worm pipefish (Nerophis lumbriciformis) is the most common pipefish found on UK shores. They are long, slender fish that looks like a worm or a piece of seaweed. They can get to 15cm in length, have a small dorsal fin behind the head and are dark green in colour. If you look closely at their head, you’ll notice a small snout similar to a seahorse.
Rockling
Rockling is a larger rock pool fish species that resembles an eel. There are two different types of rockling found in rock pools. The first is the shore rockling (Gaidropsarus mediterraneus) which can get up to 25cm in length, are black in colour and have slippery skin. The shore rockling has three barbels on their face – two above the top lip and one on the chin.
The second rockling is the fivebeard rockling (Ciliata mustela), which is very similar to the shore rockling and can grow to the same length. This rockling has five barbels around its mouth – two above each nostril and one on the chin.
Cornish sucker
The Cornish sucker or shore clingfish (Lepadogaster lepadogaster) is an interesting find in a rock pool and a comparatively small fish, growing to 7cm! This cool fish can be easily identified by their duck-billed like mouth and their sucker, which is a modified pelvic fin that allows them to stick to the underside of rocks. They are reddish-brown in colour and have two distinct blue dots above their eyes on their head, as well as two tentacles above each nostril.
