To many reef keepers biodiversity is the key to a beautiful tank and a healthy ecosystem. Some of my favorite moments enjoying my aquariums are discovering a new hitchhiker that has come in on my live rock. Many organisms such as sponges, feather dusters, snails, and the occasional coral can help beatify a tank and are often proof of a thriving mini ecosystem. But some stowaways cause more trouble than they are worth. Some can be dangerous to your fish, while others can harm you, and if released into the wild some can harm the environment. This article will focus on the identification and removal of some of nastiest and hardest to remove of these organisms.

Aiptasias/Majano Anemones

Description

Aiptasias or glass anemones are small light brown, almost clear, anemones usually less than an inch long. However, they can grow to 3-4 inches long. They possess thin long pointed tentacles. Majanos on the other hand can take many disguises. They too are small ½ - ¾ inch long, and come in many different colors from green to brown. Its tentacles are short and rounded. Often these anemones are confused with button polyps, zooanthids, or other small anemones.

Problem

The problem with these organisms is two-fold. They pack a powerful sting that can injure surrounding corals and fish. Also, if left unchecked they reproduce quickly and can take over a tank. Often the inexperienced aquarist will become excited to see a new anemone in their tank. That excitement quickly turns to frustration when these anemones multiply and begin to dominate the aquascape.

Solution

There are a couple of different things you can do to fight back against these anemones. First is physically picking them off of the live rock. This method doesn't always work because these anemones can regrow from the smallest remnants. Another solution is finding a predator to eat them. Peppermint shrimp are recommended for Aiptasias and Copperbanded Butterflyfish might eat both anemones. The problem with each of these species is finding an individual that will actually eat the anemones. You can never be 100% sure what an animal will want to eat. Also the Butterfly fish may pick on other coral polyps, such as zooanthids when it has eaten all of the Aiptasia and majanos. The best solution for these anemones is using chemical agents to kill them. Products such as Joe's Juice, Red Sea Aiptasia-X and Aqua Vision Aquatics Aiptasia Solution can be very effective in getting rid of this problem. The real solution is vigilance. After the initial removal you must check on a regular basis for any return intruders. Even the smallest anemone can recolonize your aquarium.

Bristle Worms

Description

Bristle worms vary in length, 1 to 12 inches, and color, red, orange to brown. They are easily identified by the hair like bristles protruding from each segment on both sides of it body. They are mostly nocturnal. The best way to find them is waiting until it is dark and using a flashlight to search your tank.

Problem

There is still some debate on weather or not most bristle worms are actually a problem. Recently, most experts have said that small bristle worms are helpful at eating detritus. It's when they become larger, most people agree, they start to cause problems. When they reach 4-5 inches there is not enough detritus to sustain their diet. This is when they can start to attack coral, other invertebrates, and even fish. There are some worms that rely solely on SPS corals for their food supply. You will know right away if you have one of these species, since you corals will be affected.

Solution

The best solution for bristle worms is physical removal by trapping them. There are many commercial traps available on the market. Also, the Acclimate, by Reef Gently, is another useful tool for removing these imposing polychaetes. Just remember that the bristles can deliver a painful sting and larger specimens can and will bite, so handle with caution, preferably with a pair of tongs or gloves.

Mantis Shrimp

Description

Mantis shrimp look like a mix between a shrimp and a lobster. They have the tail and body of a lobster the head of a shrimp. They possess a pair of raptorial claw that can either spear or club its prey depending on the species of mantis. They are one of the most aggressive and deadly accurate hunters in the ocean. Of the more than 450 known species, most are small, 2-3 inches. Others, however, can grow to 12 inches. Mantis shrimp in the home aquarium are often very elusive and hard to find until it's too late. A loud clicking sound coming from inside the tank and your fish are disappearing are good indicators that you have a mantis shrimp.

Problem

The problem with mantis shrimp is simple to identify. They will kill almost anything in the tank. Also the clubbing species are capable of breaking glass aquariums.

Solution

There are many commercially available traps that work well in capturing mantis shrimp. Caution should be taken when putting your hands in your tank as these are aggressive hunters and capable of inflicting a powerful punch. The strike of the larger species have been measured to equal the force of a .22 caliber bullet.

Special Note

Some people have started keeping mantis shrimp in species specific tank. They are truly fascinating animals. They are known to have the most advanced vision and the fastest strike of any animal in the world. If you decide to keep one, be careful and please do your research.

Caulerpa taxifolia

Description

Caulerpa taxifolia is a marine algae that resembles a small fern. Its branches are feather-like, 1 to 3 inches long, and grow upward out of the substrate.

Problem

This algae grows quickly and can easily take over a tank. It is also toxic to fish. Caulerpa taxifolia has been designated a U.S. Federal Noxious Weed and is currently prohibited in the U.S. It has reached this designation because if released into the wild it can overrun entire areas of local ecosystems. This has been the case in California and the Mediterranean Sea. Even though it is banned, importation is possible since it can grow from the smallest fragment left on live rock.

Solution

Special care should be taken when getting rid of these algae. It is recommended that you place it in a bag and freeze it before disposing of it in the garbage. This said the best way get it out of your tank is simply to pick it out by hand. There are no known predators as of yet, since it does contain a toxin.

Rock/Hairy Crabs

Description

Most people can recognize the standard crab, so I won't try to reinvent the wheel. The focus here though is not hermit crabs which can be helpful cleaners. Some standard crabs can also be cleaners but it may not be worth the risk if it starts eating other inhabitants.

Problem

When most people discover a hitchhiking crab, they are elated, as I know I was when I found one. Joy quickly turns to disgust most times when the crab starts pick at coral and sometimes attacking and capturing fish. Most crabs are opportunistic omnivores eating anything they get there little claws on.

Solution

Make sure to quarantine all live rock to avoid introducing these to your tank. If a crab does manage to sneak by (they are very sneaky) you may have to pull out a lot of rock to get to them.

Acropora eating Flatworms

Description

This flatworm is opaque to white in color, and is mostly oval in shape. They are very difficult to notice in the aquarium. If you have an Acropora that is not doing well, a closer look at the newly bared coral skeleton may reveal tiny brown egg sacs. This is your best indication that you have a problem.

Problem

The main problem with this flat worm isn't that they will eat your acropora; it's that they will devour it. As there name states they only attack Acropora. Colonies that are being attacked first exhibit a loss of coloration and eventually tissue recession from their base.

Solution

Along with other invaders discussed in this article, there are many options to try when addressing a flat worm infestation. First thing to do is remove all Acropora from the infected display, even apparently healthy colonies. There may be free swimming individuals in the tank. Without a food source they will starve. In quarantine you can use medications such as Salifert's Flatworm eXit, or Tropic Marin Pro Coral Cure; follow the directions on the bottle. Freshwater dips are also helpful, as long as the temperature and pH are the same as the quarantine tank. Ten to fifteen seconds in the fresh water is usually adequate to loosen the flatworms hold. Make sure to shake off as many worms before placing the colony back in quarantine.

Another option it to do a Lugol's iodine dip. The downside to these treatments is that they do not affect the eggs. The best way to get rid of the eggs is to scrap them off the coral.

Whichever option, or combination of options you choose, you will need to keep the Acropora in quarantine for at least a month to allow for the flatworms in the display to starve. During this time you will need to do 100% water changes of the quarantine water making sure to clean the tank well to kill any free swimming individuals.

Montipora eating Nudibranchs

Description

These tiny animals commonly called sea slugs and are related to snails. They are no bigger than a grain of rice, white, with ruffled edges. There eggs are tiny white dots laid in tight clumps.

Problem

Again the problem is in the name- They eat only Montipora corals.

Solution

Similar to the treatment of Acropora Eating Flatworms, all Montipora corals need to be moved to quarantine. There they can be removed from the coral using a siphon hose. Using an airline hose works the best. As with the flatworms, freshwater dips and medication may also be useful. Use the same regimen for water changes as mentioned above.

Red Bugs

Description

Red bugs as they are commonly looks like a small red or orange mite. It is actually a very small crustacean about a ½ mm long.

Problem

These little mites will feed on Acropora. In high numbers they will cause a colony of Acropora to begin losing coloration. If the proper actions are not taken the health of the coral will degrade until it is too late.

Solution

Treatment for these little mites can be difficult. Most have had success with Lugol's solution. Quarantine is the most important treatment. Once an outbreak is isolated it is much easier to contain. On a side note these are a natural food source for Dragonface Pipefish (Corythoichthys haematopterus). Some people have introduced red bugs into a pipefish tank as a supplement to normal feedings.

Red Slime Algae

Description

Red slime algae isn't an algae at all. It is a colony of cyanobacteria that can imitate a blanket of algae. It can come in a variety of colors from red to blue-green.

Problem

While cyanobacteria are present in low numbers in virtually every body of water, including your aquarium, they can be an unsightly problem in large numbers. They often take advantage of poor water quality including elevated nitrates and phosphates. Like algae this bacteria needs light to survive and will cover live rock, coral, and anything else not move in your tank to get it.

Solution

Once it gets foothold in your tank, cyanobacteria are hard to stop. The sheets of bacteria you already have need to be siphoned away during your next water change. You will need to address water quality to avoid its return. Your water should be tested for nitrates and phosphates. Consider feeding less, filtering more, or both. Also think about using RO/DI water since tap water contains a normal level of phosphates. There are also several products on the market that can help. Ultralife Red Slime Remover, Boyd Chemi-Clean, and Blue Life Red Slime Control all work really well when used as directed.

Marine Ich

Description

Marine Ich is a saltwater parasite called Cryptocaryon irritans. It is invisible to the naked eye, and can only be identified after a fish in infected. Tiny white spots will appear on the skin. These spots are actually the fish's immune response to the parasite. This parasite has a complicated lifecycle and can only be treated in its free swimming larval state.

Symptoms

Your infected fish will be lethargic and will have erratically swimming, breathing problems, loss of appetite, cloudy eyes, an increased mucous layer, and frayed fins. Because home aquariums are closed systems these parasites multiply quickly and overwhelm your fish.

Solution

There are many treatments out there that can help cure Cryptocaryon. For fish-only systems you can lower salinity to 1.009 specific gravity or 14ppt. You can not use this method for reef tanks since it will affect your corals and other invertebrates. There are also several medications on the market: Ruby Reef Kick-Ich, Chem-Marin Stop Parasite, or SeaChem ParaGuard. Read all instructions carefully before using a medication on you system.

Prevention

Sometimes the hardest thing to do is getting rid of an organism once it has been introduced to a tank. Along with everything else in aquarium keeping, the best solution is prevention. I prefer to quarantine everything, before it goes into one of my tanks. A quarantine tank is especially helpful for new live rock. I wait to see what comes out of the rock and if I like the hitchhiker, I'll keep it. If not, the stowaway never makes it into my aquarium. This quarantine time also serves as a final curing time for my live rock, eliminating any chance that it will foul my tank.