Care for Zoanthids

Zoanthids are also called colonial anemones, button polyps, zoos or zoas, but however you refer to them, these are the easiest of creatures for a beginner saltwater hobbyist to care for. Native to tropical oceans they are an excellent addition to a tropical saltwater reef fish tank. They require the same water quality, salinity and temperature of most corals and reef fish. Zoanthids can be distinguished from corals as their tentacles are in multiples of six. Zoanthids come in a range of pastel, neon and bright hues usually with the tentacles and oral disk different colors.
  1. Buying Zoanthids

    • Always purchase cultured zoanthids rather than wild gathered zoanthids. You have better color choices with cultured zoanthids and they are less likely to die from stress as they are already acclimated to saltwater tank culture. Buying wild gathered zoanthids can lead to depletion of wild colonies and the eventual destruction of ocean habitat.

      Choose brightly colored zoanthids that are open (have their tentacles extended) and are adult sized or near to reaching their adult size. Zoanthids that are pale or have a washed out color or show signs of browning are not healthy and should be avoided.

      Keep new zoanthids quarantined from your other aquarium fish and corals for at least 10 days to ensure you don't introduce disease or pests into your reef tank.

    Tank Requirements

    • To be successful with zoanthids your saltwater reef tank should have a water temperature between 74 to 80 degrees F and a pH of 8.1 to 8.4. Invest in a protein skimmer to ensure good water quality and a pump that will create a moderate currant. If your zoanthids are not thriving add a phosphate reactor to your saltwater reef tank. Use metal halide lights or power compacts for lighting.

    Placement in the Tank

    • Zoanthids should be placed where they have room to spread. These creatures can be invasive in the right conditions and should be kept away from other corals and clams in your saltwater tank as they will happily colonize (grow on) these species.

      Place zoanthids in an area where they will receive an intermittent medium to strong currant from your water pump. This currant washes nutrients and food over the zoanthids and is essential for their health. If you see zoanthids with long tenticles chances are the currant is too weak. If your zoanthids are refusing to open fully they are probably in too strong a currant.

      Zoanthids are happiest growing on rocks although they will also grow directly on aquarium glass, sand or other features in the tank.

    Lighting

    • All zoanthids have a single cell algae called a zooxanthellae in their tissue. This algae uses photosynthesis to produce nutrients it shares with its host. For the photosynthesis to occur all zoanthids need light exposure. Individual zoanthid light requirements are based on their color with pink zoanthids needing stronger light than other colors. As a general rule all zoanthids need medium to bright light. A zoanthid's color will fade if exposed to too much light or if it does not receive enough light.

      If you don't know the exact light requirements for your newly purchased zoanthid place it on the bottom of your saltwater reef tank and slowly move it closer (higher in the tank) to the lights. Allow your zoanthid to stay in the same spot for 4 to 5 days before moving again. Watch your zoanthid closely for signs of color fading or browning. If your zoanthid's color changes move it deeper (away from the lights) into the tank.

    Feeding

    • Zoanthid's symbiotic relationship with zooxanthellae algae meets most of their nutritional requirements, however, some types like to be fed dehydrated shrimp or pellets.

      Most zoanthids will eat excess fish food and fish waste. Correct placement in your saltwater reef tank will cause the currant to carry these within reach of their tentacles.
      If your zoanthids are languishing you can target feed them 2 to 3 times a week by using a pipette to place food directly over the tentacles. Do not prod or try to force feed your zoanthid with the pipette. The downside to this is that fish may recognize the pipette as a food source and become conditioned to pick at the zoanthids in an attempt to feed.

    Making More

    • When zoanthids are correctly placed in a saltwater reef tank and are receiving the right amount of food and light they will happily start spreading. Place a small piece of rock near a thriving colony. Eventually zoanthids will colonize the rock this usually happens within a month. You can then remove the rock, with the attached zoanthids, to sell to other enthusiasts or to trade for another color zoanthid. This is referred to as fragging.

      Zoanthids very rarely reproduce sexually in reef tanks.

    Handling Zoanthids

    • Zoanthids are toxic, they contain a neurotoxin, and you should always wear gloves and goggles when handling them. They can and will sting and they will squirt water if irritated. Always wash your hands after handling zoanthids.