Fish Guide Costa Rica

Most common fish species found in Costa Rica & Eastern Pacific

Fish Identification Guide

⭐ Common Fish Species in Costa Rica & the Eastern Pacific

⭐ Test yourself — take our Fish Identification Quiz!
⭐ Perfect for divers & students to improve Fish ID skills
⭐ Join our Marine Conservation Program in Costa Rica
⭐ Help collect real data on local fish populations

FISH-ID QUIZ

Choose a Fish Category

1. Disks and Ovals / Colorful

The first category of disk and oval shaped fish are very important to learn. They are colorful, large and very obvious and the three main families that make up the group can be found on almost every dive.

3. Sloping Head / Tapered Body

This third group of “fish-like” fish, are very important to learn. The are common on most dives and are also highly sought after as food fish. It is especially important to monitor these fish to provide data for fisheries management. Snappers can be very difficult to tell apart from the similarly shaped grunts. One helpful hint is to look at their tails. Snappers tend to have straight, flat tails. They are also known for their habit of snapping their mouth open and shut when caught on hook and line. They have very sharp canine teeth that can provide a nasty bite to the unsuspecting angler. Look closely on your next dive and you may see the small teeth protruding from the side of the mouth. Grunts on the other hand, have slightly notched tails. They get their name from the grunting sounds they emit when threatened. These sounds are created by rubbing together bony teeth plates located in the back of the throat. Since the teeth are in the throat, a diver will never see protruding teeth on a grunt, only big blubbery fish lips.

4. Small Ovals / Damselfish

While divers tend to first notice the larger, more obvious fish on a dive, after a short while the challenge to find new species leads them to change their search image to look for smaller, previously unnoticed fish. Generally, the first new species a diver will encounter will belong to the small oval shaped group. This group is broken into the damselfish and their close cousins the chromis. Damsels are like the surgeonfish in that they eat algae. They do not roam around grazing, but rather tend to small algae gardens like a farmer. These areas are guarded fiercely as the algae farm is the damsels food source. For that reason you can think of the damselfish as not just territorial, but Dam- selfish with its territory. Many damselfish have distinctly different colors as juveniles, often being much brighter and more colorful when they are young and becoming drab with age. (much like us humans!) For this reason, the juveniles have been heavily collected for the aquarium trade and are under heavy fishing pressure. As part of the REEF Fish Survey Project, divers are asked to monitor the juveniles and adults separately in two of the damselfish species – the Cortez damselfish and the giant damselfish.

5. Heavy Body / Large Lips

Heavy bodied, large lipped fish belong to the seabass family. We tend to refer to the larger seabasses as groupers and the smaller seabasses as bass or basslets. These fish are extremely important food fish and are under increasing threats from heavy fishing pressures. Monitoring these fish can help provide valuable data to aid in their protection. Most seabasses are hermaphrodites, meaning the same fish will be both a male and a female during its lifetime. The groupers are all born female and later change sex to become male. Most large groupers also congregate each year to spawn at a specific location, making them easy targets for emerging positioning and fishing technology.

6. Swim with Pectorals / Obvious Scales

The fish in this group all use their pectoral fins to swim with rather than the traditional tail swimming of most other fish. The scales are also quite large and obvious. These fish can also be hermaphrodites, like the groupers, with some fish changing sex and others staying the same. Intermediate and adult fish often have very different appearances compared to the always-male terminal phase. This means learning two colors to be able to ID the same species of fish. Most of the pictures shown in this curriculum are terminal phase males, unless noted.

8. Small, Elongated Bottom Dwellers

The small bottom dwelling fish often make up the most interesting fish to watch during your dive. Their approachable nature and interesting behaviors make them great fishwatching finds. Blennies tend to be slightly larger than gobies, but are most easily recognized by their curved body posture and expressive faces. Gobies, though similar in their habitat requirements, tend to sit flat and straight on the bottom. The jawfishes actually live in a burrow in the sand that they excavate and maintain.

11. Eels

Though looking like snakes, eels are fish. There are several different types of eels, and we will look at two – garden eels that live in burrows in the sand and moray eels. Moray eels have a bad reputation mainly due to the constant opening and closing of their sharp toothed mouths. However, this is not a threat to divers, as this action pumps water through their gills. Most eels are actually very shy.

How to use this fish guide

Diving and snorkeling give us the opportunity to explore one of the most beautiful and mysterious habitats on Earth.

The Eastern Pacific Ocean is a vast expanse of marine wonder, teeming with an incredible diversity of marine life. One of the most fascinating aspects of this ecosystem is the array of fish families that inhabit its waters. Among the numerous fish families found in the Eastern Pacific, Costa Rica stands out as a particularly rich and diverse hotspot.

The vulcanic rocky coastline and offshore islands host a remarkable range of species that have adapted to various niches and habitats. This fish identification guide helps you to look into some of the most common fish families found in the Eastern Pacific.

For your convenience this fish guide is divided into 12 categories based on commen features of fish families such as size, shape, color, behavior and markings. Study each of the categories and learn to identify common species of fish and their families.

If you enjoy fish identification we highly recommend you join our Marine Conservation program and help us monitor the fish populations and contribute to science and conservation in Costa Rica !

Marine Conservation
Program Costa Rica

Dive the best dive sites in Costa Rica with tropical, fish, turtles, eagle rays and reef sharks while contributing to vital conservation efforts.

⭐ Explore Costa Rica’s untouched diving frontier
⭐ Hands-on marine conservation training & certifications
⭐ Work with expert dive pros & local NGOs
⭐ Make a real impact on ocean conservation
⭐ 1–4 week programs & Eco Divemaster Internship

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