There are times when a fish owner can no longer maintain his or her aquarium. Your fish may have died and you decided against acquiring new ones, or you are upgrading to a larger tank. What should be done with the tank? Here are a few options and suggestions you may find helpful.
If your fish have died, don't just dump the water and stick the tank in the shed. Wash everything thoroughly with hot water and allow it to air dry, then store everything in a plastic garbage bag to keep bugs and dust out. This is especially prudent if you are upgrading to a larger aquarium, because you can use the smaller tank as a “hospital” or quarantine tank later on.
If you're not upgrading, then consider giving your tank away. You save storage space and don't have to worry about cracking the tank by inadvertently throwing exercise weights on top of it. Most used tanks are difficult to sell, but you can usually find someone who needs the tank. Especially worthwhile, and often tax-deductible, are schools, reptile rescue groups, and your local animal shelters.
Schools and medical facilities are also good places to donate your tank, fish and all. After all, your tank is already established and your fish are healthy (or they should be), and what a great way to bring instant pleasure to the recipient of your aquarium! Just make sure you share your knowledge of fish-keeping as well, so that the fish can continue in good health.
Should you decide to donate your tank and fish, you should prepare to safely and easily transport them. As a rule, for short distances, you can safely transport the fish in very minimal water (enough to cover them so they can pass an adequate amount of water over their gills to breathe). You can also save some of the extracted tank water in a bucket and use it to refill the aquarium once you reach your destination, although adding clean, treated water works just as well. It is important to have a secure lid on the tank so the fish won't jump out. Moving can be very stressful for fish, and they often react by jumping out of the tank.
For longer distances, you may want to sedate your fish with your veterinarian's help. Or you may want to “bag” your fish in a clean, clear plastic bag with 1/3 water and 2/3 air, rubber-banded closed. (Remind the new owners to float the bag in their tank water to equalize temperatures.) If you have reservations about packing your fish for transport, most pet stores should be able to provide helpful advice.
Finally, if you have an expensive and elaborate aquarium (with or without the fish) that you want to sell or trade, you can contact your local pet store. Almost all pet stores have a bulletin board where one can advertise for free. Likewise, these same stores often “buy back” healthy fish that are exotic, larger, or unusual.
So with minimal effort, finding a new friend for “Finny” doesn't have to be sad or troublesome.