At one time or another, all of us have chased fish around an aquarium until either you or the fish gets exhausted and gives up.  This frustrating practice of chasing fish with a net, causing extreme cloudy water, and eventually moving/removing every piece of decor or live rock is not the best way to catch fish.  The fish not only get stressed (not good if the reason for removal is disease treatment) but suffer considerable damage to the protective mucus layer as the fish scrapes itself on rock and your fast moving net.

I’ve been doing this years. With all of us using more live rock in both reef and FOWLR tanks, it is becoming near impossible to remove fishes the old fashioned way.

Recently, I wanted to remove all the fishes from my 60 gallon reef tank. I wanted to do this not because of disease treatment, but to experiment with a persistent nutrient/algae problem to see how much the fish contributed to the nutrient load.  Like most reef setups, I have live rock stacked almost to the top of the tank along the back wall.  One of the fish in there is a small 1-inch Goby that darts in and out of tiny crevices in the rock. Even if I removed every piece of rock, trying to find which piece the Goby would be hiding in would be a nightmare.  Besides, many of my early SPS frags have grown out across the rock “fusing” them together, and there no way to get the rock out without breaking corals.

Frustrated by this, I went looking for fish catching alternatives.  Anthony Calfo has spearheaded this effort with several threads and articles. I decided to try some of these methods and see how well they actually work.  So here is a list of fish catching methods supplemented with my own experiences.

The Drain Method

When I first read about this, It sounded like too much work for me. Basically, this method involves draining the tank. Yikes! If I’m going to do that, I might as well remove all the rock and use a net!

Believe me, this is so simple and quick you have got to try it. I caught all the fish in my reef tank (including the tiny Goby) and had everything back the way it was in less than 30 minutes. Not one piece of live rock was moved.

Go to the hardware store and get one or two Rubbermaid trash cans, depending upon the size of your tank. Also pick up a 8-foot length of one-inch diameter vinyl tubing. You set the trash can in front of your tank and use the tubing to siphon out the water.  On my 60 gallon tank, it took less than 3 minutes.  You can move a lot of water through a 1-inch hose very quickly.

As I was draining it, I saw none of the fish as they were all hidden in the rock structure.  My first thought was that they’ll be trapped in the dry rock crevices as the water level dropped. Amazingly, as the water got down to maybe 3-4 inches, all the fish instinctively swam out of the live rock and congregated right in front of the tank. I just took my net and scooped them out.  The smaller fish swam across the front of the tank, but all in all there was very little chasing with my net. Next time I do this I will dig out a section of gravel and make a little depression where I believe the fish will all congregate.

To refill the tank, I dropped a submersible pump in the trash can and let the return hose run water over the live rock (like a waterfall) to prevent stirring up the sediment. The refill process actually took the most amount of time, probably 10 minutes to get the tank filled up again. If I had a bigger pump on hand, I probably could have filled the tank almost as fast as I drained it.

I can assure you that the short period of time that the live rock and corals were out of water causes no harm. Live rock is shipped dry and remains so for days during shipping. Corals quickly “slime over” with a protective layer when removed from the water.

If you’re tank is less than 100 gallons, please try this method because it really, really works with minimum effort.

The Corral Method

For tanks over 100 gallons, the drain method is not too practical since you need a lot of trash cans. My second choice (which I have used many times with 100% success) is the Corral Method. Like rounding up cattle from a pasture, you create smaller fenced in areas in your tank where the fish have nowhere to go except into your net.

Get some eggcrate from the hardware store. You need to make two identical panels. The width of the panels is the inside width of your tank (front to back). The height of the panels are the water depth in the aquarium  plus 1 inch. The idea is to place these two panels into the tank on both sides of the fish, trapping it in a small area. You stick the panels down into the gravel, and the top of the panels stick out of the water. Wrap the end with duct tape so the edges of the eggcrate won’t scratch your tank or hands.

When you start messing with your tank, the fish will bolt into their favorite hiding places. Most likely, this will be behind or in a piece of live rock. If your aquarium is aquascaped with several “islands” of live rock across the tank, it’s easy to place the partitions on both sides of the island where the fish is hiding. Once cordoned off, you may need to remove a piece or two of live rock in the corral zone to get at the fish.  It will usually swim out in a frenzy and be stopped by the eggcrate panels on the left or right, where you can easily net the fish without much chasing

If your live rock is situated as a continuous row across the tank, you will have to move some pieces around to make some narrow slots down the gravel for the partitions to fit in. It is best to let the fish hide on its own, observing where the fish likes to go when threatened. Clear a narrow area on both sides of the hiding place.  As long as you don’t move the rock where the fish is in, it will stay put as you get the partitions in place. If the fish is small enough where it could pass through the holes in the eggcrate, wrap it fiberglass window screening before applying the duct tape.

There is a little bit of work in making the eggrate partitions, but once you have them they can be used over and over.

The Bait-and-Switch Method

In an established tank, your fish probably race over to a certain spot where you feed them every day, hovering right at the water surface to get some tasty food. Perhaps some even taking it directly from your fingers. This method involves food in one hand, and a net in the other.  At the right moment, you simply swipe the net quickly down into the water, capturing the fish while its mind (and mouth) are on the food.

This has worked for me, but not every time. Fish can bolt away very quickly when they see the net.  If you miss, you won’t have the opportunity to try this again for several days or even a week.  Fish learn about the net trick very quickly and will become skittish at feeding time. This method works best if you’re trying to a catch a single fish. It is not practical to catch every fish in the tank or any fish that doesn’t eagerly come to surface to feed.

The Night Stalker Method

This method involves catching a fish while it is sleeping. It only works for fish that sleep out in the open like Clowns, Cardinals, etc. Some fish will “drift” to the open while it sleeps, so you may have to time this a bit.

You need to make sure the room is in total darkness. If you have moon lights, cover a few of them with pieces of black electrical tape. Without moon lights, you can use a small flashlight such as a Mag-Lite. Some people say to cover the lens with a piece of red cellophane tape. I’ve tried it both ways and it doesn’t make much difference.  Just don’t point the flashlight right at the fish- point at the back of the tank or off to the side.

Wait a few hours after the tank lights go out, then take a plastic specimen tank (a.k.a “convalescent home”) and VERY SLOWLY submerge it.  Move it under the fish and raise it out of the water. voila!  You’ve caught your fish. Be sure and move it to your holding tank without turning on any lights.  If it wakes up, it will likely panic and jump out of the specimen tank.

The “Gone Fishing” Method

This method involves using a fishing hook and bait. This is no joke. Catching a fish in this manner is a lot less stressful than chasing it around the tank for 30 minutes. The lip injury caused by the hook heals quickly and causes no harm. Think about this. There are thousands of anglers who exercise the “catch and release” method in sport fishing to maintain fish populations- and it works.

Go to a sporting goods store and get some small trout hooks. The smaller ones (size #18 and higher) are small enough to accept a single mysis shrimp. Use a small file to remove the barbs, which will minimize lip damage and make it easier to remove the hook. Drop your line in and wait. When you hook the fish. use a plastic specimen tank to remove it from the water.

The Bag in a Bag Method

This is a method created by Anthony Calfo. It is a way to catch really shy or elusive fishes in a reef tank. Dwarf Angels, Basslets and the like can be had this way with little disturbance to the tank as long as you have a little bit of patience.

Take a fairly large plastic bag (new and sturdy 2-3 mils preferably). Size is relative to the fish being caught. But typically a 10X22 bag catches most home reef aquarium fishes. Fold the top of the bag down about 2 inches 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. MOST IMPORTANTLY lean it against the rockscape so that shy fishes are more likely to slip by or in it.

The Bait: cut the corner off a plastic sandwich bag and put some frozen brine shrimp in it then 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 with a 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 “motherload” 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 elusive fishes. It takes time though… and patience. But if you are afraid to drain your tank or use other methods, this may be an option.

In summary, these are the most popular methods for catching fish, but there are also lots of other ways that people do it. Some of these include the 2-liter soda bottle trick where you cut off the top and invert it, placing it back in the bottle to form a funnel. Some people have had success with placing a small mirror in the tank. The fish gets so obsessed in chasing its own reflection that you can scoop it up easily.

whatever method you use, don’t get frustrated and wind up tearing your tank down to catch a fish. Use one of these methods and you will relieve the stress for both you and your fish.