Star Savvy
The Conical Spined Sea Star is a wildly underrated invertebrate. While the whole world thinks they want a Purple Linckia (and some of you experienced aquarists may) what most of you want is Echinaster sentus. They are wildly more durable than many other commonly available Sea Stars, absolutely gorgeous, and to top it all off are super useful! What more could you want?
Echinaster sentus got its common name from its looks. They are a classic shape and have a look you'll be familiar with if you've spent any time on Florida beaches. They are often dried as souvenirs for tourists in kitschy beachside gift shops, and it isn't uncommon to find them in tide pools or on the reefs while snorkeling the keys. In addition to being found in near-coastal waters of Florida, they can be found up the Atlantic coast up to the Carolinas, throughout the Caribbean and down to the nearshore waters of Brazil. They come in a few different colors but are usually orange or red but brown and even bluish ones happen. Regardless of their color, they are all spotted with off-white to golden cone shaped (conical) spines that give them the look of a five-armed aquatic cactus. They are going to generate some commentary from everyone who sees your tank.
They usually don't hide either, so they are out and about a lot. They'll spend their days and nights migrating around the tank, over rocks, across the substrate, even up the glass (which is really fun to see, when you get to see all their little “feet” moving them along.) This is also a great time to feed them because you can put small pieces of meaty food like Gamma Mysis, Brine, Tubifex, and even Mini-bloodworm next to their legs and they'll move the food toward their centrally located mouth. When they're on the glass, you can see the whole thing. As an omnivore grazing Star, they won't often need target feeding in large, established, and preferably heavily stocked aquariums where there is plenty of leftover food and fish waste, but in smaller tanks, or more sparsely stocked tanks, you should target feed your star at least a couple times a week. Keep giving them little morsels of meaty food until they stop taking them, then try it again in a couple days. If you see them losing weight, ramp up the feeding. If they aren't interested in your offerings, wait a day, or feed less per feeding. You can also utilize Nutramar Algae and Color Boost Shots and place one in the path of the Star, and they'll happily consume as much of it as they want, unless they fish get to it first.
Conical Spiny Stars are most often collected in shallow water, and this means they are adaptable to a wide range of conditions, which makes for a pretty good aquarium invert. We suggest keeping them in temps between 70 and 78 but would probably be okay a few degrees colder or warmer, as long as these changes happen fairly gradually. Keep salinity stable around 1.025 and nitrates low under 10ppm and lower would be better. Keep the pH as stable as possible between 8.0 and 8.4. While these stars are pretty adaptable, they tolerate changes best when they happen slowly. Avoid any copper at all costs.
Most of you aren't going to actually plan your display specifically for a Sea Star, and while we think that's kind of a shame, we get it. These stars will love surfaces; the more rocks, crooks and crannies you can give them, the more places to graze algae and hunt down detritus there will be. They don't specifically need any specific tank size. As long as you keep water quality good and stable, and you did a lot of supplemental feeding, you could keep a Conical Spined Sea Star in a ten-gallon desktop nano. This being said, we'd suggest keeping one in a display that was 55 or 75 gallons to give them a better selection of natural food for them to graze on.
Picking the tank mates is more important than picking the tank size. Fish wise, these aren't going to bother any fish that isn't already dead. The opposite is not true, so do not house Echinaster sentus with notorious nippers like Puffers and most Triggerfish as they do not heal injuries easily. In regard to invertebrates, Stars in this genus are low risk with corals, though you should monitor them and remove them if they develop a taste for something other than meat, detritus or algae. We would caution you to not house them in tanks that have decorative clams. Obviously, they are fine in FOWLR (Fish Only With Live Rock) tanks.
Most Sea Stars are sensitive to being exposed to air, so try to keep them submerged as much as possible when transferring them into your display. Acclimate them slowly to avoid the parameter shifts we wrote on earlier; we suggest using drip acclimation (see our acclimation article). The Conical Spined Sea Star is a gorgeous addition to the home aquarium. They are easy to keep and hardy and are a definite show / conversation piece. At full grown they can be five or six inches from tip to tip and are active all day and night! If you want a Sea Star that is big on beautiful and low on labor, it's time to consider adding one of these to your tank. Head over to your LFS and ask about getting you a sustainably sourced Echinaster sentus from Quality Marine today!