You may have a hard time figuring out the sex of a particular fish if you don't know much about fish anatomy, but finding out the gender of a fish is certainly something you can do. To find out the sex of a fish, you must observe the size, shape, appearance, and behavior of your fish. For more information about your fish, you can search for books and videos about fish, as well as consult a fish expert.
Step
Method 1 of 3: Observing Fish Appearance
Step 1. Compare the size of your fish during the spawning season
In most fish, such as koi fish, the body of the female fish tends to be larger than that of the male fish. This can be seen specifically during the spawning season, where the belly of the female fish tends to enlarge. To measure fish of the same species, you can watch them swim side by side, take photos of each of your fish, or catch a fish using a net to quickly measure using a ruler to measure the length and width of the fish.
- This happens because the female fish contains her eggs in the abdomen. When the female fish lays eggs, her body size becomes the same as the body size of the male fish.
- If you catch a fish using a net to measure it, try to keep the fish in the water and then put a ruler in the water to measure it. You can get an idea of the length and width of your fish this way.
Step 2. Look for a lump on the forehead of your fish, if you find a lump in that area, it means your fish is a male fish
Pay close attention to the area between your fish's eyes and mouth. If there is a large, prominent lump in the area, it is likely that your fish is a male fish. This lump is called a nuchal hump, and is found in many types of fish, such as tilapia, angelfish, Oscar, and discus.
Some species of fish do not have these lumps, but the presence of these lumps can be a characteristic feature of male fish
Step 3. Watch for changes in the shape and growth of your fish's body parts during the spawning season
Generally there are fine barbs, bumps, or shiny scales on the male fish to attract the attention of the female fish.
For example, male broomfish will grow fine spines on their pectoral fins and around their mouths and heads. Although female broomfish can grow similar fine spines/barbels, their fine spines/barbels tend to be smaller
Method 2 of 3: Finding out the Gender of a Specific Fish Species
Step 1. Compare the sizes of the cycloid's dorsal fin
In general, the dorsal fin of male cyclists is larger than that of female cyclists. If you have several cyclones, pay attention to the size of their fins as they swim side by side to determine their gender.
Examples of cycloid fish include tilapia, angelfish, oscar, and discus
Step 2. Watch for the occasional bumps on the goldfish to look for male goldfish
In spring, pay attention to the forehead, gills and pectoral fins of your fish. If there are small clusters of lumps in these areas, it is likely that your fish is male. But don't wait too long to observe these bumps, as they only appear in the spring and will disappear when the goldfish spawning season ends in early summer.
The size, color, and shape of these bumps may vary, but they are generally concentrated in several small areas of the fish's body
Step 3. Look for aggressive broomfish in your tank for male broomfish
Male broomfish can be aggressive towards other fish. Watch out for broomfish that swim fast to scare off other fish swimming nearby. If you have an aggressive broom fish, then it is most likely a male fish.
Other names for broom fish include algae suckers, janitor fish, and suckermouth catfish
Step 4. Look at the triangular fin near the guppies and mollies' tails for male guppies and mollies
Near the back of the fish, near the tail fin, you can see a small triangular fin. This fin is called the anal fin and can be used for sexual reproduction. Use your magnifying glass if necessary, as these triangular fins are difficult to see on small fish.
In addition to mollies and guppies, you can look for this triangular anal fin on swordtail, platy, and platy wagtails for male fish
Method 3 of 3: Looking for Other Sources
Step 1. Visit the nearest pet store or spawning grounds to talk to a fish expert
If you are having trouble figuring out the sex of your fish, you can visit the fish shop or fish farm where you bought your fish. Talk to your partner about the types of fish you have, and bring pictures or photos of your fish if possible. They may be able to help you determine the sex of your fish, or introduce you to someone more skilled in the field to assist you.
- Even though employees in pet shops are generally not equipped with in-depth knowledge of all kinds of fish, it is not impossible that you can still find fish experts working in the nearest pet shops.
- Never take your fish out of the tank to take them to the store or to the spawning grounds, as your fish will stress out and die.
- Spawning sites can give you tips and advice on breeding your male and female fish so that your fish can lay eggs during the spawning season.
Step 2. Look for other sources such as videos and pictures about fish on the internet
Search for the fish species you have on YouTube, and add the keyword “sex search” to see videos created by experts and fish farmers as they identify the characteristics of different fish. These videos can give you an idea of the traits you should look out for in both male and female fish.
You will be easily confused when looking for and watching the various videos available, so make sure you watch videos about the species and types of fish you have at home
Step 3. Learn what kind of fish you have
Start your search by looking for sources about the types of fish you have because there are so many different types of fish. Visit your local library and look for books such as the Encyclopedia of Fish Physiology, which contains information about many different types of fish. Look for the sections on classifying and “finding out the sex” of fish.
For example, if you have tropical fish in your aquarium, read a book about tropical fish
Step 4. Ask questions in online forums to get answers from fish enthusiasts
There are many online forums that focus on breeding marine life, raising fish, and setting up aquariums. If you have questions about the sex of your fish, share photos of your fish on these forums and ask the members of these forums for help. Most likely someone on those forums will be able to help you.
- Try to be specific about the type and species of your fish, and label photos of your fish as necessary to make sure people who see the photos don't get confused.
- Don't forget to check the forums as often as possible to see the answers from the forum members.
