Tips on Moving Saltwater Fish

Fishes in plastic bag for sale
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There are many occasions in a fish or critter's life in captivity that put it under a great deal of stress in a relatively short period of time. From the critter's point of view, the top three (in no particular order) are probably: being introduced into an established tank, cycling, and transporting.

Introducing a new fish to an established tank can be a pain, but with a little research on compatibility and some innovative thinking (a temporary barrier or rearranging the "furniture" in the tank) will minimize most major problems.

Cycling a new tank shouldn't be a problem nowadays. With the use of some of the new starter bacteria on the market, practicing the "seeding" method, or adding live rock, the ease, and quickness of tank cycling has advanced greatly over the years.

This leaves transporting the critters as the main potential problem. If you follow some basic rules, it isn't all that difficult. If you don't follow the rules, you are setting yourself up for a disaster.

Initially, the three main things to concern yourself with, as far as packaging, is the type of critter being transported, the length of time in the bag, and the method of transport. Even picking up a new tank critter at your local fish store takes a little planning as there are a few things that you can do that will increase the probability of your new tank occupant getting home in top shape.

The four main things the critters will require in transit are the same that they require anywhere:

  • Oxygen
  • Good water quality
  • Low to no toxins in the water, particularly ammonia!
  • Proper temperature

Taking these four main factors into consideration, and knowing how to handle each one will help to ensure a safe and happy trip for your critters.

From the Live Fish Store to Home

The trip home from the LFS is the easiest since you will be in direct control of everything from the beginning of the trip. The LFS will partially fill a plastic bag (ask them to double bag the critter) with water, inflate it with air (O2 is always better, but few LFS do this) and seal it, probably with a rubber band. You are then handed the bag and sent on your merry way.

To begin with, make sure that the LFS, or you, add a good ammonia neutralizer to the bag water. Don't let the LFS salesperson talk you out of it, as ammonia builds up very quickly in a bag. The few pennies it costs either yourself or the LFS is very cheap insurance.

On the trip home, rather than just dropping the bag in the trunk or on the back seat, you might want to invest in a small styrofoam cooler to transport the bag or bags. This will help keep them upright, shield them from rapid temperature changes and calm the fish by keeping it/them in the dark.

If the fish appears to under stress (rapid gilling, listless), you might want to open the bag and manually aerate the water by hand. Using small battery operated pumps with an air stone work well to eliminate the hassle of having the manually aerate the water if needed.

When you get home, make sure that you acclimate the new arrival. The chances are that the shipping water from the LFS will be quite a bit different from yours, as well as the bag water temperature from that in your tank. Introducing a new fish directly into the main tank is not wise. It is highly recommended to use a quarantine tank for new arrivals.

For any major aquarium move, the key to success is to plan ahead. Don't wait until the last minute for anything. Make sure that you have your bags, rubber bands, oxygen supply, boxes, tape, insulation, packing water materials, have the fish cleaned out, substrate and decorations cleaned, and capture nets or cups. A couple of extra 5-gallon plastic buckets always come in handy, too.

For the love of your critters take the time to pack them to ensure that they make the trip safely, even if you are going a short distance.

Bag Preparation

You will probably need several different sized bags for your shipment. You will probably be able to find used (or new) bags at your LFS. They might charge a few cents each, but it is worth it. The bags should be a minimum of 2.5 mil thickness. For the more significant spinner fish like Surgeons, Triggers, etc., use triple layered 3 mil bags.

Different kinds of fish need more or less room in a bag, and more or less water. Keep in mind that it isn't so much the "water" that ensures a good "ride" for the fish; it is the column of O2. Most fish will do well in a bag that they can comfortably turn around in, depending on the length of the trip. Just enough water to keep them covered while swimming upright, plus an extra 1/2" of water in the bag is all that is needed. However, for larger more active fishes, like Wrasses, Triggers, and Groupers as examples, they need more water coverage.

  1. Make an "envelope" out of newspaper, using about two or three thicknesses, to put between the bottom 1/3 of the bags. If a fish spine pokes through the first bag (and this happens a lot), the newspaper will help stop the spine from going into the second or third bag, helping to retain the water. The other thing to consider are fishes that have sharp teeth, like larger Wrasses and Triggerfishes. Many times they will try and bite through a bag, so the use of a newspaper liner is wise.
  2. Tape the bottom of the bag, eliminating corners that the fish can wedge themselves into. To do this, insert your hand into the prepared bag (before you put the water in), positioning it upside down on your hand. Using your index finger, stick it into the bag corners (one at a time) forming a point. Fold the corner inwards toward the center creating a triangular shape, while using two-inch clear or brown packaging tape, tape the corners to the bottom of the bag. The bottom of the bag should look like the diagram (above, right).
  3. Use Oxygen when you gas your bags for shipping. It might sound difficult to find, but it isn't. Nearly all shops that do auto work have an acetylene torch. You can use this quite nicely.
  4. Buy a small supply of a good quality Size 64 rubber bands. You will need at least two for each bag. You will also need a supply (one for each box) of large trash bags (35+ gallons). These will be the final insurance against a total leakage that floods the back of your car, or the airline cargo bay.

Shipping Water

Your shipping water is easy to prepare. If you are using Sea Salts, mix the water in a large bucket or larger container. Mix the water to about 1.019 SG. The lower SG reduces stress for the fish and makes the trip easier for them. Add about 2 tablespoons of AmQuel (you can't overdose) to 32 gallons of water. Use a good antibacterial medication (Nitro-Furozone) in the packing water to help protect the fish from potential bad bacteria exposure that can occur from fish pooping in the bag. Fish in a bag over an extended period of time exposed to fouled water can result in the fish becoming ill shortly after the move.

Aerate the water with an air stone for several hours before packing. The more O2 you can dissolve in the water, the better for the fish.


How you are shipping (vehicle, airlines, etc.) determines the type of boxing you will need. If you are coming home from the LFS, a simple cardboard box will work. This will protect the bag and keep it from tipping over.

If you are transporting a distance in a vehicle, you will want to go with a more secure containment. You can use an inexpensive styrofoam cooler, an ice chest or go with an insulated shipping box that the pros use. The pre-formed "styros" with a cardboard liner are the most popular.

Preparing Fish for Transport

Don't feed your fish for two or three days before shipping. This helps them clean out their digestive track and avoids the "fouled bags" that eat up oxygen and choke the fish during shipping. Surgeonfishes are renowned for this problem as they have very long intestinal tracts for digesting high fibrous algae. It takes them longer to clean out than most other species. If you are shipping your substrate, perform a thorough tank cleaning four or five days before shipping. This will get rid of any excess material in the substrate and still give the resident bacteria a period of time to repopulate before shipping. Shake any excess material from your corals and live rock before shipping.


This is where all your planning and preparation pays off. You have all your bags made up, your boxes standing by, your packing water made up and well aerated, the fish are cleaned out, your tape and rubber bands (Size 64) are nearby.

  1. Open one of the trash bags and put it in the box, folding the bag down over the sides of the box to get it out of the way. Put some of your packing water into the bags and stand them up in the box. Rolling the top edges of the bags down makes it a lot easier to get water and fish into the bags and the taped bag bottom helps the bag "stand up" in the box.
  2. After catching the fish give them a 3 to 4-minute freshwater (dechlorinated) bath before putting them in the bags. You don't have to do this, but it is an easy way to help ship only "clean stock."
  3. Take a look at all the fish in the bags. Make sure that they are "comfortable" and can move around in the bags. If they look too crowded, move them into a larger bag. You can also "spotlight" them at this time, using a flashlight. This will let you know exactly what they looked like (no torn fins, parasites, etc.) before they were shipped.
  4. Now you have to "gas" the bags. Unroll the top edge of the bag, then gather it together, like you were going to blow it up and pop it. Push down on the top of the bag, squeezing all the air out. Insert the O2 line into the bag and inflate it, leaving about three inches of the extra bag to seal with the rubber band. Take out the O2 line, holding the gas in the bag, then twist the bag top several times. Using the rubber band, seal the bag top. Pull the rubber band tight as you do this.& You can use several rubber bands if you like.
  5. Make sure that the height of the bag is low enough that it will fit comfortably into the box after the lid is on. Tie off the rubbish bag with a rubber band and put the lid on. If you are using a liner, close it and tape it shut.
  6. If you are shipping your substrate, place it in the bags with just enough water to cover it, then inflate and seal the bags as above. For corals and live rock, roll them in a layer or two of the newspaper, place them in a bag with about 1/2" of water and gas the bag before sealing. The newspaper will help keep them from drying out. Or, you can ship them immersed in water, which is much more expensive if you are shipping via the airlines.


Even if you are shipping to your end destination via the airlines, you will have to transport the fish in a vehicle to get them to the airport. Secure the boxes in your car/van in such a way as to keep them from tipping over or sliding around. Fish can take quite a bit of abuse in a bag without any problems, as they are cushioned by the water they are in. However, if the box should turn over, you run a higher risk of the spines of an excited fish piercing the unpadded top area of the bag, allowing the water to drain out of the bag.

Protect the boxes from heat and cold at all times. That sunshine streaming through the window on your face might feel good to you, but even with styrofoam protection, the inside of the box will heat up if exposed to direct sunlight for any length of time. The same is true of cold temperatures. If you are driving through Montana in January, don't leave the fish boxes in the trunk of your car, while you are parked at a motel for the night. If at all possible avoid moves during the hottest or coldest times of the year.

If you are going to be shipping via the airlines, make sure that you contact them well ahead (days or even weeks) of time to find out what their requirements are as far as containers, drop off time before the flight leaves and of course the price for shipping. Most airlines like you to drop off your shipment several hours before the scheduled departure time. This allows them to organize the load before departure.


When you get to your destination, unpack the fish, substrate, etc. from the boxes as quickly as possible. If the trip was of any length of time, they would be under a certain amount of stress. Acclimate the critters slowly into their new home. It would be a shame to lose them after all the effort you have gone through to move them.