Setting up a marine fish tank? Not to be discouraging, but it takes a lot of work to set up and maintain salt water fish tanks and many who try don't succeed. Here are 5 common mistakes hobbyists make. If you can avoid these, it'll go a long way toward you owning a vibrant, healthy tank!

1. Choosing a Small Tank

While having a small tank (ie. less than 30 gallons) may seem like a good idea, but I'd advise against it, especially for newbies. One of the keys to maintaining a successful marine fish tank is to keep the water conditions stable. When you have a small tank, with a relatively low volume of water, it's much more susceptible to changing water conditions which can be a big stress for salt water aquarium fish and other tank inhabitants. When choosing a tank, start as big as you can afford, but don't go below 30 gallons, especially if this is your first tank.

2. Getting Impatient

It takes time for a marine fish tank to establish itself and for the water to cycle to the point where it's ready for fish. It can take a good  3 - 6 weeks for the cycling process to occur. In that time, don't add any more than 1 - 2 hardy fish. Jumping the gun and adding more fish before the tank cycles can cause a lot of headaches down the road for you. 

Another area where being impatience can get you in trouble is, after your tank has cycled, adding too many animals to your tank too quickly. It's an exciting idea to add as many fish as possible as quickly as possible. But doing so will severely tax the filtration capabilities of your tank and have a negative effect on water quality. 

Bottom line: taking it slow and steady and you'll be rewarded with a much healthier, stable marine fish tank.

3. Tank Overload

This is another mistake that marine fish tank owners commonly make. There are so many beautiful fish, corals, and invertebrates to choose from, you want as many as possible. But overcrowding your tank will have a negative impact on things. First, many salt water aquarium fish are territorial and need there space so putting too many in a tank can result in turf battles that can lead to injury or death.

An even bigger problem with overcrowding is that it will produce high levels of biological waste that your filtration will not be able to keep up with. This will produce water that is toxic to fish and other tank inhabitants.

To avoid this scenario, think about what types of creatures you plan to put in your tank before adding any. Do some research on the species you want to add and see how big they get, how territorial they are, etc. Then plan out the types and quantities of each that are appropriate for a tank your size and stick to the plan!

4. Overfeeding

This is probably the most common mistake made by marine fish tank owners. It's understandable. Fish get very excited when they're fed and it's fun to watch them dart around picking morsels of food out of the water. Plus, since you can't pet or cuddle with a fish like you can with other pets, feeding is one of the few ways you can really interact with them.

And while you definitely need to feed your fish, doing it too often or giving them too much food is a big problem. First, as with humans, eating too much can make fish sick. And second, more food equals more waste in the aquarium. And more waste means you can have problems with water quality that can lead to health issues for your tank's inhabitants. 

Food requirements vary by species, so it's important you understand what to feed your fish, how much to feed them and how often to feed them and realize it's probably less than you think.

5. Not Keeping Up With Maintenance

Marine fish tanks are a lot of work to maintain. You'll need to clean the filter, clean the glass, perform water changes, test the water and more on a regular basis. It's easy for this, less glamorous side of owning a salt water fish tank to slide. But if you let things go for more than a month or so, you may start to see a degradation in water conditions which can spell doom for your fish. To stay on top of things, try breaking tasks down into more manageable chunks so you're not doing it all in one fell swoop.