Filling a 30 gallon saltwater aquarium with animals can be a stressful task. There are just so many options to choose from. This guide will go over a few unique fish and crustaceans that can be kept in a saltwater aquarium. There are many others out there but these are a few that really stand out to me that aren’t incredibly hard to keep.
1. Yellow Assessor
The Yellow Assessor, otherwise known as the Golden Assessor Basslet, is not a very common fish in a reef aquarium but it is fantastic! They can get a little territorial like other basslets but overall are quite a peaceful fish that will not bother invertebrates. It is perfect for reef aquariums! Provide quite a bit of hiding spots and rock work to dull the aggression towards other fish. This fish is carnivorous so providing meaty food such as mysis shrimp or brine shrimp are a must! It will max out around 3″ in size and is an excellent addition for aquariums that are 30 gallons or larger. They have a gorgeous yellow body with a touch of red on its fins. A unique feature of this fish is that at times it will swim along rocks sideways or upside down. It usually gives new fish owners a scare but it is perfectly normal!
2. Geometric Pygmy Perchlet
The Geometric Pygmy Perchlet is a grumpy looking fish with red and white coloration on its body. It has a much higher dorsal fin than many other fish. It can be a little territorial to other tank mates but it normally minds its own business. This fish is carnivorous so providing meaty food is very important!
It will max out at 2 inches in size and will do very well in a 30 gallon reef aquarium. One unique attribute for this fish is that it will actually perch on rock work and sit there very still waiting for food.
3. Watchman Goby + Pistol Shrimp
Now a watchman goby is not very unique but there is great possibility that if a pistol shrimp (otherwise known as a snapping shrimp) is also introduced into the aquarium, the two will pair up, share a burrow, and live life together. The goby will keep a watch out and protect the shrimp and they will at time share food. It is really interesting to observe these two working together and protecting their burrow. The pistol shrimp is also able to use its claw to create a “snapping” sound that can be heard outside of the aquarium. This sound is used to scare off predators and the pistol shrimp uses the claw as a weapon to catch prey.
Both of these creatures are great for aquariums because the watchman goby will help keep your sandbed clean sifting for algae and plankton while the shrimp will collect uneaten food that falls to the bottom of the aquarium. For the most part, the snapping shrimp is harmless to all other animals in the aquarium with the exception of small shrimp. The watchman goby will max out at a size of 4″ and this duo is a perfect combination for a reef aquarium.
4. Mantis Shrimp
The mantis shrimp should be kept alone in a species tank. They are highly intelligent and very aggressive. Due to their aggression only one mantis shrimp should be kept in an aquarium. Their very colorful bodies are truly fascinating and their hunting tactic is even more so. They primarily use their club-like appendage to hunt and are able to attack crustaceans, fish, and other unsuspecting animals with their powerful strike. They have enough power to crush snail and crab shells. This is why they should be kept alone in an aquarium. Crustaceans are recommended to throw in from time to time as a quick snack for the mantis shrimp. Otherwise, the mantis shrimp should be fed live feeder fish, frozen scallops, shrimp, and other meaty food.
A mantis shrimp can use its claws that are as powerful as a .22 caliber bullet to break the glass of its enclosure. I would highly recommend using acrylic instead of glass for the mantis shrimp’s enclosure. Other than that, it is quite easy to setup their aquarium and are fairly easy to care for.
Hopefully this list gives a good idea for hobbyists that are looking for something different in their aquarium or are looking for a very niche animal to keep. Marine animals are very unique and have great personalities so keeping them is always a great time! Some require precaution before keeping but after that saltwater systems are quite enjoyable.