You can’t deny that some fascinating creatures lurk in our oceans, and some can live in home aquariums. Aquarium oddities are called “oddball fish” among the aquatic hobbyist community, and they provide a talking point for any tank and endless entertainment. The downside is that many oddball fish are delicate with specific care needs, so aren’t the best choice for beginners. If you want to know more about these strange and wonderful creatures, dive into this list of the six weirdest-looking saltwater fish.
1. Boxfish: Interactive, Omnivorous Pufferfish
Lifespan: 8 years+
Size: 5 – 8 inches
Care level: Expert
The boxfish takes top place on our list of the weirdest-looking saltwater fish. These unique, square-shaped creatures are related to the toxic pufferfish and may look seriously genetically modified, but they are entirely natural. Boxfish have unique personalities and enjoy interacting with their owners, but are delicate and sensitive to water changes, so they are not ideal for beginners.
Boxfish are omnivores and thrive on flakes, pellets, and frozen or freeze-dried fish food. They are generally peaceful, but they secrete toxins when they feel threatened, which is toxic to tankmates and can potentially kill them. Several boxfish are suitable for home aquariums, including the Yellow Boxfish, Spiny Boxfish, and Common Boxfish. The Striped and Spotted Boxfish are the most common choice for saltwater fish tanks because they only grow to around six inches long.
2. Frogfish Are Ambush Predators
Lifespan: 2 – 5 years
Size: up to 14 inches
Care Level: Intermediate
The bizarre frogfish certainly deserves a place in any list of weird-looking fish. It’s a member of the anglerfish family and looks nothing like your average tank dweller. When you view it from certain angles, it resembles a frog. Frogfish don’t move a lot and blend in with their background, and it’s easy to mistake them for sponges or anemones.
Frogfish are poor swimmers and crawl across surfaces with modified pectoral fins and may disturb rocks and ornaments. They are deadly ambush hunters and spend weeks in the same spot waiting for their food to come to them. The best way to feed them is with defrosted frozen food on a feeding pole.
Frogfish cope well in small aquariums but produce a lot of waste, so you must stick to a rigorous cleaning schedule. You must keep these aquarium oddities in a single-species tank because they eat anything that fits in their mouth.
3. Lionfish May Eat Smaller Tankmates
Lifespan: 10 years
Size: 7 – 15 inches
Care Level: Intermediate
With its distinctive striped colors and long dorsal spines, the lionfish is the most recognizable entry on our list. Lionfish are deadly, and their spines deliver a painful sting, which can be fatal to other fish. It can also cause painful swelling in humans or a severe reaction in people with sting allergies. They aren’t great swimmers and usually scoot along the floor, so they need a deep, soft aquarium substrate.
Lionfish generally aren’t aggressive but are opportunistic carnivorous and eat anything that can fit into their mouths. Don’t keep them with small, slow movers such as seahorses, inverts, and clownfish because they will be an easy meal. These are large fish, so they need a substantial aquarium, and you shouldn’t keep them with other lionfish. The Fu Manchu, in particular, are incredibly aggressive toward each other. The best lionfish tankmates are fish of a similar size and nature, such as groupers, large angelfish, and tangs.
4. The Longhorn Cowfish Has Horns and Spikes
Lifespan: 8 years+
Size: 5 – 15 inches
Care Level: Expert
The Longhorn Cowfish is another unique fish to add to your tank and is closely related to the box fish. The difference is that they have more spikes and distinctive horns, but their care needs and personalities are the same. Like boxfish, they also secrete toxins when threatened, which can be fatal to tankmates.
Longhorn Cowfish are aggressive toward other horned fish, so avoid keeping them in groups and ensure they have ample space. The best tankmates for Longhorn cowfish are docile, passive species such as clownfish, gobies, and cardinalfish. Cowfish are carnivorous, so be aware that they may eat small crustaceans.
5. Pipefish Are Docile but Challenging Pets
Lifespan: 3 – 8 years
Size: 8 – 15 inches
Care Level: Expert
Pipefish are unique creatures and cousins of seahorses. They have long, narrow bodies and come in many colors and patterns. They are masters of disguise and incredibly shy, so you must provide them with lots of hiding places, aquarium plants, and anchoring spots. The pipefish likes to grip plants with its tail and wait for prey. These enchanting creatures have complex care and diet needs, along with requiring pristine water conditions and targeted feeding with live food several times daily.
Pipefish are rewarding pets due to their enchanting behavior. Mated pairs are monogamous, and couples perform a courtship ritual every morning. Like seahorses, male pipefish carry the eggs and give birth to live young. Pipefish are delicate, passive creatures, and ideally, you should only keep them with other pipefish or seahorses. They are weak swimmers and can’t compete for food in a mixed tank.
6. Shrimpfish Swim Vertically to Camouflage
Lifespan: 5 – 8 years
Size: 8 inches
Care Level: Expert
The final entry on our list of weird-looking saltwater fish is the shrimpfish, or razorfish. The most distinctive thing about these guys is that they swim vertically instead of horizontally, which helps them blend in with seagrass. They have slender silver bodies and long pointy mouths, and they perform enchanting displays when you keep them in a school. Shrimpfish are challenging for first-time aquarium owners because they have tiny mouths and need live food several times daily. They also produce lots of waste, so keeping their habitat clean is demanding.
Shrimpfish are peaceful creatures, and their best tankmates are small, docile fish, such as pipefish and seahorses. They are incredibly timid and need plenty of hiding places, such as aquarium plants, caves, and overhangs, to help them feel safe.
