Large Marine Carnivores in the Home Aquarium by Robert Farnsworth, a Marine Depot Staff Member
Having a large marine carnivore in your home or office aquarium may seem like a cool idea. Imagine the oohs and aahs from houseguests and business associates! However, before you take the plunge, there are many things you'll need to consider first. The most important, of course, being that these animals are living creatures that will depend on you for survival.
Large marine carnivores eat protein-rich, meaty foods. In an aquarium, these animals are fed live, fresh and/or frozen foods, or a combination thereof. They grow quite large and often live longer than other, more common saltwater aquarium species.
If you are interested in keeping large marine carnivores, it is extremely important to have a deep understanding of how these animals behave, how to properly care for them and how much time and money it will require to do so. Unfortunately, the more minute details are, more often than not, overlooked and the quality of life (or the life itself) of these animals are sacrificed.
So what can you do to prepare?
Start reading and asking questions. We're a great place to start! Your question will be answered publically and will help others who have the same question you do. If you have several questions or would prefer to speak one-on-one, you're also welcome to contact us directly. Other experienced hobbyists are a terrific source of information so ask your fellow aquarium club members or hit up your favorite marine aquarium message board and start taking notes.
One of the first things you'll learn is that you are going to need a large aquarium, perhaps considerably larger than the aquarium you have now, to care for the animal for the extent of its life. Does your current tank measure up? Is an upgrade in order?
Large marine carnivores are often kept in species-specific aquariums. That is why it is common to see large fish-only (FO) aquarium systems that house only large carnivore species. High-end external pumps are frequently utilized to provide sufficient flow and filtration throughout the system. ReeFlo pumps were specifically designed for this niche of the hobby and deliver flow rates up to and beyond 4500 gallons per hour (GPH). Investing in a quality, energy-efficient pump will save you time and money in the long run plus you'll enjoy the benefit of minimal heat transfer into the tank.
If you are putting a heater inside your predator tank, avoid glass heaters since they can be easily broken. It may not be the first thing that comes to mind when setting up a tank for large marine fish but be forewarned: marine predators and other large fish are capable of producing powerful forces, even underwater, and can easily shatter a glass heater. I'm pretty certain you'd prefer coming home to a beautiful aquarium and not fish soup.
Aquarium Pharmaceuticals' SmartHeater is a great heater choice for a large marine carnivore tank. It is virtually indestructible and available in 5 sizes ranging from 50 to 300 watts. It includes a built-in heater guard and gives you peace of mind that “Moby Dick” won't break it and fry himself while you're away. Azoo's Titanium Heater, available in 50 to 500 watts, is a viable alternative and is also well-reviewed by hobbyists.
Adequate filtration is always a necessity but particularly in predator tanks since large carnivores produce larger waste particles. That is why I strongly encourage utilizing high-quality mechanical filtration for this type of setup. If you're going the FO route, I recommend an inline-type pressure filter that can effectively filter out the large particulate matter that will become present in the aquarium. Nu-Clear canister filters can handle up to 2500 GPH and will perfectly accommodate a large aquarium system. Pentair Aquatics also produce excellent pressure-rated inline mechanical filters for this application.
Proof that size does matter
Most shark species that can live in a home or office aquarium will require a tank of at least 500 gallons. Depending on the species, some sharks will outgrow a 1000 gallon (or larger) aquarium. Do you have the space to accommodate such a mammoth tank? Are you willing to give up the shark you've loved and cared for in a mere matter of months because it outgrew your aquarium?
Large Angelfish are another popular saltwater aquarium predator that requires a large tank. Large Angels in particular need a long tank for maximum swimming space in order to grow and interact with other fish species on a natural level.
Triggerfish can be extremely aggressive and, if introduced into a small tank with other fish, can cause serious havoc. Even common eels found at your LFS can be highly aggressive, eating everything that swims and growing between 4 and 6 feet. A grouper with a mouth large enough to swallow a fish whole can literally clear your tank of its inhabitants in a matter of minutes.
I cannot stress this enough: please study the specimen(s) you are interested in keeping and make sure you plan ahead so you can house and care for them throughout their life.
It is vitally important to keep mechanical filter cartridges clean; if not, they end up becoming nitrate factories, especially in marine tanks. You should use chemical (carbon) and biological (rock or media) in addition to the mechanical filtration to maintain the highest quality water for your pets.
After doing your due diligence in research, acquiring and setting up the proper equipment, the next thing you'll need to consider is the animals' nutritional needs. As mentioned earlier, most carnivores will benefit from regular feedings with live and frozen foods. What you're basically looking to do is to make sure their diet is rich in protein that mainly comes from food sources found in the ocean. Check out the ingredients in the food you're considering; many frozen foods are made using natural ocean ingredients (read: animals) like clams, squid, silversides, brine and mysis shrimp. Frozen fish foods are available in general and species-specific formulas, so it's likely you'll be able to find a food that fits your animal's needs. Rod's Food and Ocean Nutrition are two well-respected brands that create both general and specific fish food blends. Ask around, too, and see what others are using.
For a large marine predator, live food is obviously the most desirable and natural source of nutrition. Although widely available and oft-utilized, goldfish are not the best live food choice for a marine carnivore. Goldfish are sometimes treated with copper and can be nutritionally deficient, creating eventual health problems for your pet(s). Guppies, feeder shrimp and platies are a healthier alternative. Your best bet though is to feed a marine animal marine-sourced food, such as marine feeder shrimp or the aforementioned frozen foods.
We also recommend using a set of super-sized tongs, like H2O's Life Handy Grab Aquarium Tongs, for feeding, reaching and grabbing within a predator tank. Human hands and fingers may be a good source of nutrition, but we've never tested this internally, so you can leave us a comment and let us know how it's worked for you... if you're able to type with that hook you have for a hand.
Caring for a marine carnivore can be an exciting and rewarding venture. However, as with any pet, make sure to do thorough research before buying. That way you'll understand what it takes to create a healthy environment and how to properly care for them for their lifetime.
Good luck! And remember, if you have any questions, let us know.