Receiving Fish Step-by-Step

If you have never received fish that have been shipped by mail before, here is how to handle them when they arrive. Remember, they have been traveling for a long time and need to be moved into a tank as quickly as possible.

1) Immediately open the double bags and pour the fish and the shipping water into a fish-safe bucket or similar container. One of the mini plastic tanks with a snap on lid sold for keeping reptiles works very well. Whatever the container, make sure it is covered. It’s important to remember so I’ll mention it AGAIN, ALL FISH CAN JUMP, AND FISH JUMP WHEN THEY ARE FRIGHTENED!

2) Don’t bother with the traditional ‘bag float.’ That works when fish are coming from the local store, but not when they come by mail. Set up a drip line by using a piece of airline tubing and draping it from the tank they are going into and down to the container with the fish.

Start a siphon and allow the water to drip into the container. You can regulate the flow by kinking the tube and wrapping a rubber band around the kink until just a few drips come out of the line at a rate of about one drip per second, or you can tie a loose knot in the tubing with the same result. Some hobbyists even use a gang valve with the line running into the tank and over the side into a bucket.

Whichever method you use, let this run until the water in the container is about double what it was when you started. Carefully pour off most of the water until there is just enough to cover the fish when they are upright. Let the container fill again. This procedure slowly introduces the fish to your water and allows the temperature to equalize. It’s not a bad idea to add an ammonia neutralizer to the water, too. This will help reduce stress on the fish while they are adapting to your water.

3) The fish are now in about 90‐95% your water. Take a net and carefully net the fish out and move them to their new home. DO NOT ADD THE SHIPPING WATER TO YOUR TANK.

4) Darken the tank. Leave the lights off for the first day. This will allow the fish time to settle in and recover a bit from the shock of transport.

5) If the fish are showing signs of stress, add a little salt to the water―up to one teaspoon per gallon. This will help them to deal with any osmotic stress, and help their slime coats to recover, which will help prevent disease.

6) Even if the fish shipped to you are tank raised, healthy and disease free, the stress of shipping may make them vulnerable to disease. I strongly recommend putting them into a quarantine tank for a couple of weeks. This allows them time to recover from the stress of shipping and to get used to your water conditions and food. No matter the source, even from close friends, I ALWAYS QUARANTINE NEW FISH FOR AT LEAST A MONTH. Better safe than sorry. I can tell you from personal experience that failing to quarantine can cost you a lot of lost fish, and it is usually the most valuable and irreplaceable fish that are lost!

7) Feed them sparingly. If shipped properly, they have been without food since two days before shipping. This allows them to be completely empty during shipping and cuts down on potential pollution in the bag, which can kill. While fish can easily go for seven or more days without food, the stress of shipping, coupled with a lack of food can weaken healthy fish enough to allow disease to set in.

8) In spite of what you read and hear at the local shop, don’t worry too much about pH or hardness. Fish are remarkably adaptable animals and can handle different water conditions without serious problems. Many fish in nature experience extremes of pH, hardness, and temperature in just one day, especially in the tropics at the beginning of the rainy season. More fish are killed by hobbyists playing with water parameters that they don’t really understand than by any other factor except ammonia. The important thing is to give them time to adapt to your water, which is what the drip line system does.

Note: Nearly all fish can easily tolerate moving to harder, warmer, or higher pH water. If they are going to softer, cooler, or lower pH water, give them extra time on the drip – maybe even cutting it down to one drip every 2‒3 seconds.

Items needed to receive fish:

1) Fish-safe bucket or other container with lid. Covered plastic reptile cages work very well.
2) Dripline made of airline, with rubber band, knot, or valve to adjust flow.
3) Quarantine tank. Add salt to the water if fish are showing signs of stress.


Quarantine is a practice of isolating new animals or plants from all others for a period of time until they have been judged to be free of disease. Not many hobbyists do this, but all should. I can’t tell you how many times I have taken the shortcut and been sorry for doing it later, even when I thought the new fish were from a ‘safe’ source. Better safe than sorry.

A quarantine tank can be anything from an unused 5 or 10-gallon tank to a small plastic critter container or a 5-gallon bucket. It should be set up with a biological filter, a heater (if needed), some hiding places, and a tight fitting cover (remember that all fish jump). It doesn’t need to be set up all the time, just when you purchase new fish. Fill it with half clean, new water and half with water from the tank the animals or plants will eventually be going into. Have an established sponge filter going in another tank that you can move into the quarantine tank. After the quarantine period, sterilize it and then move it back into the other tank until you need it again.

It is a good idea to feed the fish well while they are in quarantine. This will help them recover from the stress of shipping and rebuild their fat reserves. I often feed them with a frozen food with garlic added. This helps clean them of internal parasites. It is also a good idea to raise the temperature a bit over what they would normally live in. This procedure will speed up the life-cycle of any parasites so they show themselves while the animals are in quarantine. You can then easily treat them in the quarantine tank without worry of damaging the biological cycle of your main tank. It is not a good idea to use a ‘shotgun’ approach and give a prophylactic treatment to the new arrivals for diseases which they may or may not have. This can cause resistant strains of disease organisms to develop. Only treat them for actual diseases which might show up. A good book on fish diseases will help here and should be a part of every hobbyist’s fish library. Without any sign of disease, the only things that should be given to the fish are garlic treated foods and/or an addition of salt to the water which should only be used if they are showing signs of stress.

After two to four weeks, if they show no signs of disease, the new arrivals can be moved into your system. If there is a sign of disease, wait two to four weeks after treatment is complete before considering them safe to move to your system.