How Much Space Does a Starfish Need?

Starfish are bottom-dwelling, star-shaped fish that can be kept in aquariums under certain conditions. Appropriate tank size is one of the most important factors when determining whether or not you're equipped to keep a starfish. The space needed per starfish varies according to the animal, as some species need more room than others because of either their size or behavior.

  1. Standard Starfish

    • Most standard starfish sold for home aquaria do not require an immense amount of room. The minimum tank size for a common starfish, such as a chocolate chip starfish, is 30 gallons, or 36 inches by 12 inches of floor space. However, this will accommodate only one animal. Adding an additional starfish will require double the floor space. Starfish suited for the "standard" amount of room include chocolate chips, sand-sifting sea stars, marble sea stars and red sea stars. Though 30 gallons is the minimum, it is recommended that most starfish be kept in tanks of at least 50 gallons.

    Special Cases

    • Some starfish are more solitary and less tolerant of water parameter fluctuations. They require more room since they need adequate space to hide. Larger tanks are also less likely to rapidly fluctuate in terms of their parameters (it is more difficult to lower the average temperature of a 100 gallon tank as opposed to a 30 gallon tank). Starfish like Blue starfish require at least 100 gallons of room per individual fish to accommodate their specific needs.

    Decor

    • All starfish need rocks or sandy substrate. The rocks allow them to hide from other fish in the tank and also help them feel sheltered, which reduces stress. The decor in your tank should also be considered when determining whether there is enough room. If the bottom of your tank is covered with rocks or decor, this may drastically reduce the amount of room your starfish has to roam. Floor space is more important than height for most starfish, so they will do better in long, wide tanks rather than tall tanks.

    Other Considerations

    • Some starfish are safe for coral reefs while others will devastate them. Some starfish may eat coral and destroy your reef. All starfish require careful acclimation to a new aquarium, preferably drip acclimation, in which water from the tank is slowly added to the water the starfish was shipped in until it gets used to it. All starfish also require full spectrum lighting and adequate filtration with temperatures in the mid-70s F. Research your particular starfish before adding it to your tank to make sure you have the right parameters for housing it comfortably.