How To Catch Fish In Your Display Aquarium
If you've ever tried to catch a fish or invertebrate from an established display tank full of plants, rocks, coral, and other decorations you know exactly how frustrating of a process it can be. You can literally spend hours trying to chase a fish around while disturbing and knocking over all your aquarium stuff in the process, this isn't healthy for you or for the fish. Another option is to remove all or part of your plant or rock scape and attempt to catch the fish in muddy water and then put everything back, but there are easier ways. Following is a list of some creative ideas to help you easily catch those fish you need to remove from your tank without disturbing everything else.
The DRAIN METHOD:
This is a simple method that involves draining the aquarium water quickly and returning it afterwards. If you don't have one you will need a water holding vessel, your local Walmart or Home Depot both have clean rubber garbage cans for less than 10 dollars. You will also need a powerhead or pump and a length of plastic tubing of a diameter that matches the powerhead output (usually 1 inch), you can acquire the tubing at Home Depot but the powerhead will need to be purchased at your local or online aquarium supply store.
Using the powerhead pump the water into your large receptacle and dig a low point in your sand or gravel where your fish can swim to low water. If you have a decent powerhead you can usually empty the majority of your aquarium water volume in a couple minutes. Don't worry about exposed rock, coral, plants, or decorations during this process, these life forms will not be harmed out of water for a short time.
When the fish you are after is in the low spot you can usually catch them pretty effortlessly without overdue stress on the fish or system. Once the fish is caught simply pump the water back into the tank the same way you pumped it out.
The JAR METHOD:
This method is most effective at catching crabs or other similar invertebrates. Crabs have very pointy feet which makes them well adapted to hold onto rocks, corals, and other substrates even in heavy water flow but they cannot hold onto glass.
Get a small to medium sized glass jar, a small pickle jar works well or any similar sized jar. Clean the jar well and then rinse it out with watered down vinegar to clean out any soap or other impurities that may be left in the jar.
Position the jar in the aquarium between some rock work near where the life form in question likes to spend their time or bury it in the sand with the mouth facing up. At the bottom of the jar but some of your favorite stinky meaty foods that you know the crab just wont be able to resist. You may catch other lifeforms as well but that isn't a problem, once you have the guy you need simply get him out and dump the rest out of the jar.
The BAG in a BAG METHOD: (The Best For Fish In My Opinion)
This is my favorite way to catch really shy or reclusive fish from the home aquarium. You can catch most fish with this method while causing little disturbance to the tank as long as you have a little bit of patience.
Take a fairly large plastic bag, size relative to the fish being caught... but typically a 10X22" catches most home aquarium fishes. Fold the top of the bag down about 2" to make a sturdy collar and sink this bag into the aquarium while removing all air from in and under it (the collar).
Place the bag expanded (fluff it out so it is a bit spacious) in the aquarium... but MOST IMPORTANTLY lean it against the rock scape so that shy fishes are more likely to slip by or in it as opposed to waiting with it in open water.
The Bait: take a tiny golf-ball sized plastic bag of concentrated live bring shrimp... tie it off, then throw it into the back of the large sunken bag trap.
Then... with a bowl of additional live brine shrimp in a slurry, you sit near the tank (lights off in the room) and occasionally squirt (turkey baster) just a little bit of brine shrimp into the mouth of the bag every few minutes as needed.
The obvious ploy here is to lure fishes to the mouth of the bag and tease them with the "mother load" in the back! (the small tied off bag of concentrated live food)
Now of course... every other fish and its brother that you do not want to catch will enter the bag first But eventually the shy fish will too... and when it does, you are sitting several feet away from the tank with a piece of fishing string that was tied around the neck of the bag, under the collar... and pull!
You'd be amazed how well this works for really shy fish. It takes time though... and patience.
HOMEMADE TUBE TRAP
Fish can be captured with a baited trap easily made at home, this works especially good for small bottom dwellers such as Gobies.
Take a plastic bottle, such as a water bottle or a 2 liter bottle (for larger fish use a bottle with a large mouth), and cut off the top. Invert the top back in the bottle. Bait trap with something tempting and wait. This may take several days. The fish will be sufficiently confused when trying to get out, that you should have enough time to pull the trap out before the fish discovers the exit.
Dragonettes don't like to go over the lip, to catch these fish you can leave one end open and partially submerge the trap in the sand. In order to trap them once they go in, you must devise a trap cover on the end of a stick. Some premade algae cleaners will do nicely.
THE NIGHTTIME KIDNAPPING
For fish who sleep in a regular spot that is relatively open (like clowns), the easiest time to catch them is at night when they are sleeping.
Well after lights out, using a moonlight LED as a guide and eyes well adjusted to the dark. Slowly submerse a clear specimen container and move it close to the fish you wish to catch. Scoop the fish up and quickly cover the top of the container. Remove the fish to it's new home, acclimating as necessary, but be kind and don't flip the lights on.
