Sea urchins have mixed reviews in the saltwater aquarium scene. Some people love them because they are fascinating to watch and make outstanding algae eaters. Others find them difficult to care for and don’t like the destruction they can cause. Whichever way you look at it, sea urchins help to maintain a balanced aquatic environment and can benefit a tank in many ways. So, in the article below, we’ll discover if keeping sea urchins in a saltwater aquarium is right for you.
Keeping Pet Sea Urchins Can Prove Challenging
Keeping sea urchins in a saltwater aquarium isn’t easy and can challenge even the most experienced fish keepers. Sea urchins are super sensitive and deteriorate quickly in unclean conditions or if the tank parameters fluctuate. When these prickly creatures deteriorate, they have an incredibly hard time recovering, and it’s difficult to revive them. First-time aquarium owners may struggle to provide the perfect conditions these critters need to survive.
Sea urchins are also challenging because they are difficult to handle and may prick you when you clean and maintain the tank. They are also destructive and will displace aquarium decorations and demolish coral. If you’re new to aquarium keeping or have sea anemones, you must thoroughly research their care needs before taking them on as pets.
What Do Pet Sea Urchins Need?
The first thing you must know about the sea urchin’s habitat is that it must live in a well-established aquarium, and the ideal tank size depends on the species. Small urchins, like the tuxedo urchin, can get by in a 20-gallon aquarium, but giant types like the long-spined urchin need at least 75 gallons.
Sea urchins eat algae. So, you must ensure there are many surfaces in the tank for algae to grow on. They also like to hide and climb, so you must provide plenty of rocks and hiding spaces. You must stick down tank decorations securely with suitable glue or epoxy because sea urchins will move things around. The best aquarium substrate for their tank is gravel or sand.
Sea Urchins Need Exact Water Parameters
Sea urchins have specific care needs; their tank parameters must be stable, and the water must be pristine. If you keep urchins, you must monitor the tank parameters daily and test aquarium water weekly for pollutants like ammonia and nitrates. Even lightly polluted water can harm an urchin’s health. The best way to keep the water clean is with a high-quality filtration system, and many keepers also use a protein skimmer. You must also change 10 to 25 percent of the water every two to four weeks.
The ideal parameters for sea urchins include:
- Water temperature of 75 to 80 F
- pH of 7.7 to 8.5
- Specific gravity at 1.023 to 1.026
Urchins don’t have specific light requirements, but the algae they eat need light to thrive.
The Best Diet for Sea Urchins
Sea urchins are generally herbivores but have a flexible diet, sometimes consuming dead and decomposing saltwater aquarium creatures. They will find most of their nutrients from algae in the aquarium, particularly coralline algae. If there isn’t enough algae in the tank for them, you must supplement their diet with algae wafers or dry seaweed. You can try spot-feeding them weekly with flakes or wafers. You must be careful not to overfeed them because leftover food will pollute the water.
It’s challenging to know if you are feeding a sea urchin enough. Many owners report that their urchins approach the top of the tank if they are hungry. In these cases, they usually stay there for a few days for daily feeding and then return to deeper areas of the tank when they are full. A good diet is crucial for an urchin’s well-being–– and a well-fed urchin is less likely to attack coral.
How to Handle a Sea Urchin
Handling sea urchins can be tricky, and you must be very gentle with them. If you are too rough, you can damage their tube-like feet and potentially prick your hand or fingers. A soft touch is key to handling these creatures because they only penetrate your skin if you use too much pressure. A prick from an urchin can be painful, and their spines can embed in the skin. Most species are not venomous, but some varieties, such as the long-spined urchin, are venomous and can sting.
If you need to move an urchin, gently slide your hand between its spines and the surface it’s stuck to. You can slowly and gently remove the creature this way. Alternatively, you can place a flat piece of plastic in the sea urchin’s path and wait for it to move onto it.
Sea Urchin Species for Saltwater Aquariums
There are hundreds of urchin species, but not all are suitable for domestic saltwater fish tanks, and each has unique care needs. If it’s your first time keeping sea urchins, you should choose one of the hardier species. It’s also a good idea to pick captive-bred urchins because they adapt better to domestic life than wild ones. Some urchins are less destructive than others, so choose reef-safe ones if you’re worried about them wrecking your coral.
Sea urchins are compatible with most reef creatures, but you should avoid keeping them with starfish because some prey on sea urchins. You should also avoid keeping them with fish that prey on saltwater invertebrates such as wrasses, hogfish, and balloonfish.
Here’s a list of the most common sea urchins for saltwater aquariums:
- Pincushion urchin – is among the hardiest species.
- Tuxedo urchin – is also a popular reef-safe species.
- Black longspine urchin – is large and grows up to 10 inches.
- Pencil urchin – is an omnivore and preys on small inverts.
- Short-spined urchin – is a small reef-safe species.
