10 Smart Ways to Use an Aquarium Catch Cup or Specimen Container

Have you ever seen those clear rectangle boxes hanging on the outside of tanks at your local fish store? This is the aquarium specimen or catch cup, one of the most versatile tools for fish keeping. It is a transparent, small container that can be used to observe fish or hold aquarium supplies. Learn about the top 10 ways we find ourselves using catch cups every day at our retail fish store and personal fish tanks.

1. Observation

When fish are zooming around the aquarium, or darting behind ornaments, it can be difficult to see them clearly. To get a better view, grab a few fish and set them up in a cup of water. The smaller space allows you to inspect the fish for disease symptoms, pick the healthiest individuals for breeding, or sort out male and female juveniles for sale. You can also use the flat, clear walls to take photos of your favorite species.

2. Transportation

Aquarium nets may be fine for moving a few fish from one tank to another, but this method can be quite inefficient if you have a large school of fish to transfer. Instead, use your specimen container as a temporary holding pen until you finish catching all of them and then move them together afterwards. To prevent fry from being eaten by predators, you can move them to a grow-out aquarium, or bring the pond fish indoors to enjoy the winter. You can also remove pest snails from one tank and feed your pufferfish aquarium.

3. Selling Fish

If you plan on selling your fish at a fish store, fish club auction, or online, you usually need to package the animals into fish bags. Scoop out some aquarium water and then place the fish you catch into the specimen container. Once you have the correct number of fish, you will be able to pour them directly from the catch cup into the fish bag. Then seal the bag with rubber bands. You can use multiple containers. The first container will hold the largest number of unsorted fish while the second one will contain the fish.

4. Acclimation

You may need to gradually acclimate your shrimp or fish to the aquarium water if they are new to it. If your animals are small enough you can allow them to adjust in the container.

1. Open the fish bag, and then pour some water and the animals into the catch cup. 2. Add aquarium water from their new home into the catch cup so that the water level is doubled. (If the water gets too high, just pour some out of the container.) 3. After 15 minutes, add more aquarium water so the water is doubled again. 4. After 10 minutes, add aquarium water to make the water double again. 5. The fish can be netted from the container and added to the aquarium.

For an even more gradual acclimation process, look up how to do “drip acclimation” using a length of airline tubing. You can calm fish that are running around in the catch cups by covering them with towels or darkening the room.

5. Breeding

An air stone, check valve and airline tubing can be added to your DIY breeder box. Keep the specimen container in the aquarium to keep it warm. Add the air stone to ensure the fish have enough oxygen. Then you can place a select pair of fish inside to increase the chances that a certain male and female will mate together. This setup is also useful for hatching fish eggs. The catch cup can be used to temporarily raise the newborn fry without fearing that they will escape with their tiny food. To provide shelter for them, add a clump java moss and other live plants. You should also regularly clean the water from their catch cup with a turkey baster.

6. Isolation

There are several situations where you may need to temporarily separate one fish from the rest of the crowd. For example, female guppies, mollies, or other livebearers that are about to give birth may appreciate a quiet and peaceful environment to release their babies. The “birthing area” will prevent the fry being eaten immediately by larger fish and will also help the infants hide from their mother.

Another case would be to isolate a fish that has an injury, is behaving oddly, or exhibits other strange symptoms. Keeping them in a specimen container with an air stone allows you to monitor their status more closely and potentially treat them with medication if needed. Read the entire article for more information about treating fish diseases.

7. Mealtime

It is a good idea to feed your fish a variety of fish foods. But it can be cumbersome to handle all those jars, slippery packages and other items. Your catch cup can be used as a food container to transport everything from one tank to the next. If you are feeding frozen foods, thaw the cubes in water inside the specimen container and use a pipette or turkey baster to squirt the liquid into multiple aquariums. This same method can be used for live fish foods such as blackworms, baby brine shrimp, daphnia and infusoria.

8. Water Transfers

The catch cup can be used to remove scum from aquariums or to replace water from nano tanks. To test water parameters with liquid reagents, you will need to first scoop some water from the tank and then fill the tubes with test water. Some hobbyists place catch cups in the aquarium, then attach the end of a hose to the container or point their Python hook at the tank while filling it. The catch cup gently overflows, protecting your plants from being damaged by the force of water.

9. Equipment Storage

A specimen container is a great place to store fish nets, algae scrubbers or other tools after they have been used in an aquarium. Many people use them as extra storage space by hanging the catch cup on the side of the fish tank to keep their favorite fish food, fertilizers, and other supplies all within easy reach.

10. Planted Tank Maintenance

One of our favorite uses for specimen containers is during the maintenance of planted aquariums. You can use them to remove floating plants such as duckweed or other aquatic plants from your aquarium. To propagate your stem plants, place the trimmings of the stem plants in the catch cup.

Now that you are aware of the importance of having a specimen container, you should get the Aquarium Co-Op Catch Cup. The walls are extremely clear to allow you to see your fish and the plastic is shatter-resistant so it won’t fall if dropped. Plus, the extra-wide handle allows you to hang it on large fish tanks with thick walls.