Click on image to find out more about each species
One aspect of rockpool life we love is the fish, each one we discover under a rock gives that what is it buzz. The problem is fish do not hang around to be identified. Our pools are home to a handful of small fish and sanctuary for many more. One problem fish encounter is being tasty, they are prime food sources. So immature sea fish of a range of species can be found in pools, if they can avoid the egret, heron, cormorant, kingfishers and child with a bucket by constantly moving and staying in the deep sections they escape the big predatory open sea fish. This habit differentiates them from the locals who utilise the pools in a different way.
Rockpool fish know their pools intimately, they have escape routes pre-planned. These vanish so easily when we come along with our nets and wellies. Cracks and crevices are the key components of a pool, weed helps but it is the ability to have a substantial hiding place that makes it home.
The rocklings are soft, sinuous and slippery, ranging from orangish to brown or olive coloured, they resemble plump eels. Often more than one lives in a pool even under the same small rock. They can manoeuvre around the pool with great easy, seemingly turning in impossible tight spots and just as you think you have caught one they flip and are gone to the next hiding place. These fish have barbules on their snouts most likely used to detect prey in the murk and sandy bottom. The number of these identifies the species.
In contrast, the sea scorpion is all about spines and tough skin, the gill covers have significant spines that easily lodge in the throat of a predatory fish or bird. Unless swallowed carefully these creatures will make a very unpleasant meal. If you handle one hold it lightly or they will happily use them against you, opening the gills to point the spines outwards. These fish have very large eyes and equally large mouths, clearly a visual hunter. A short spined species is also found so check the length on the gills. They are very placid when caught, seemingly confident in their defensive armour.
The gobies are smaller and come in a variety of species, these can be difficult to identify unless you get a very good look at the distinguishing features. They have smaller mouths and eyes than blennies, the dorsal fin is in two distinctive sections. These are the minows of the pools.
Some species need a bit of hunting to track down. The worm pipefish, resembling a dark bit of wire often hides under stones. If you carefully take apart any piles of stones at the low tide mark in gullies, especially if they have sediment underneath you might find a few. They are easily overlooked. The males brood the eggs by carrying them on their belly. They have tiny mouths (the worm has an upturned snout other larger species are open water creatures) and so eat plankton and small morsels.
Eels can be found at certain times of years, these are very difficult to catch even when you think you have hold of one it simply slips away. Young eels are very thin but not wiry like pipefish, they are not plump like rocklings. The adults superficially resemble rocklings but once you have seen one the difference will be apparent (protruding lower jaw and small if any barbules). Eels are passing through the beach, they have fascinating lifestyles to read up on.
Several species of flatfish frequent sandy or rocky pools, the outline shape and colour are diagnostic, if you find one that seems to stick to rocks it is likely to be topknot. Young flatfish actively seek the safety of shallow sandy pools so walk through these slowly dragging your feet to disturb them.
One fish not to be missed is the lesser weaver fish, this little creature lurks in the edge of the surf as it is a weak swimmer it hides just under the sand. The spine on the back injects a protein-based poison and the pain is significant but not fatal. Wear something on your feet and watch them safely, pushing a shrimp net along might catch a few but do not handle them.
Fish are an important part of the shore ecosystem, many are the top predators, others like sand eels seem to be on everyone's menu. Nets cause damage to pools so please get in the habit of baiting them out with bacon in a bottle trap or tied on a line. Not only is this more fish-friendly it allows you to see them behaving normally.