DIY Underwater Feeder

Credit: Sherri /

Modified to allow you to land the feeder on top of the coral and feed it without having to stick your arm in the tank every day. I call these lunar landers becuase it reminds me of a game that I used to play on my Apple // back in the day.

You will need some tools for this project: • Scissors or Exacto Knife
• Silicon sealer
• Flexible air tubing
• Small piece of styrofoam
• Small rubber band
• Decorative glass rocks or something similar for weights
• Empty 2 liter, 1 litter or 8oz water bottle with cap
• Drill and two bits: one the size of air tube and a much smaller bit
• Ear dropper or turkey baster – something to squirt food in the air tube

When selecting your bottle take care in getting one that is squatty like this one rather than pointy – this will help surround your coral with the food it needs rather than the food getting stuck up in the neck of the bottle.

Cut the height of your lander so that there is room for your coral inside of it.

Here I am using silicon sealer to adhere decorative glass aquarium rocks to the sides of the lander. This gives the lander the weight it needs for landing on top of your coral as well as keeping it right side up and with a little spin you can dig into your sand a little bit for a decent seal.

Drill a hole in the cap to poke the flexible air tube in. Drill a smaller hole off to the side on the cap for air to escape. This will prevent lifting or tipping if you accidently squeeze some air into the lander.

Poke the air tube through the top of the cap. Wrap a rubber band snuggly around the tube about an inch from the end and then siliconed it to the bottom of the cap. This was necessary as I wanted to drop the lander into the tank – let it sink – feed the coral and then yank the hose to retreive it without having to put my arm in the tank every time. My thinking was the rubber band/silicon combo would prevent the tube from slipping through when I tug on it – and so far so good – it works!

Blane Perun

Diver - Photographer - Traveler

Whale in Ocean