Growing live food for our reef is something I have been dabbling with for quite a few years. I find it one of the most interesting and fascinating aspects of my hobby. I love to get out a microscope or jewelers loop, and check out the fascinating part of our hobby that is known as Micro...

Phytoplankton

Phytoplankton is the bottom of the food chain in the ocean, where life begins. Phytoplankton feeds everything from tiny fish fry to the zooplankton that feed the coral polyps that line the entire reef structure.

   The group of unicellular algae that is collectively known as phytoplankton includes red, brown and green algae, plus diatoms and dinoflagulates.  The green algae receive the most attention in our hobby, maybe the misconception that they are easier to cultivate or the ease of finding these cultures contributes to this fact. The nutritional value of microalgae species varies greatly, with some being high in one or both types of omega 2 fatty acids (EPA vs DHA), others being higher in proteins and carbohydrates. A search on the www will reveal masses of information about these algae.  One of many sites dealing with nutrition

  I have found that to have the most complete nutrition for my reef and my fish fry, I need more than one alga. Growing more than one species in the same vicinity can be problematic. The spores can become airborne and contaminate each other, with the strongest species out-competing the weak. They will need a way to physically separate them. I have a backroom behind my tanks where I can physically separate 2 species.

Cultivating unicellular algae is relatively easy, requiring only a few minutes every day, somedays I do nothing. All that is needed is a consistent light source and a way to move the algae so it can receive that light. I use regular household lights, 4 foot fluorescent tubes from the hardware store. I only replace them when they burn out. I do use  a bulb type light in a $5 fixture to spotlight new cultures.

I keep my algae motile using airlines in my starter and smaller cultures, and small pumps in my larger vessels. I have found that round type vessels keep the algae from finding stagnant spots. As long as it stays in the water column, it will grow.

I use household bleach, soap and the hottest water I can stand to clean my vessels. I keep all my measuring cups and supplies in a solution of bleach next to my fish sink. I soak my pumps in the solution. I use new rigid tubing for each starter culture.

My recipe for medium is easy: Tapwater, a little less than a half cup salt mix, 3 mls F2 fertilizer and 1 drop declorinator for each gallon. I have a large population of macroalgae so I know that any unused fertilizer will be used in my system. If you don’t have macroalgae, you might use less fertilizer. You might check the salinity a few times when you first start out. I try to keep it close to the salinity of my tanks, around 35 ppt.

When I am just starting a culture, especially a fragile or expensive one, I inoculate the new culture with about 50% new mix. When I know it is growing well, I use much less of the pure culture, around 10%.

Miscellaneous tips

Air pumps: Try not to restrict your pump’s desire to push air. It will shorten it’s life. You can hook valves together and have many valves on one pump, depending on it’s capacity. After I have adjusted the bubbles, I open up one empty valve. Then, I turn it off slowly, watching the flow in the vessels. When the flow is where I want it, I leave the empty valve open to that point. This way, any excess air will leave the valve and the pump is not restricted in it’s capacity. I have had the same pumps for years.

  Using different colors of flexible tubing makes it easy to visualize which tubing goes with which culture.

Culture Vessels: I find the best vessels are glass. They are easier to clean than plastic. I can use lime remover for any build up of calcium, I can scrub vigorously to remove any scale, and they last forever.  I have found many suitable vessels at thrift stores, craft shops and garage sales. Round root beer jugs, fish bowls and vases can work wonderfully. I am not a beaker or mason jar fan. The bottoms are too flat for circular water movement,but I am sure there are some that could work well. I prefer a large opening that I can reach my hand into.

Finding cultures: I find this one of the challenging aspects of live food culture. I have found most companies that profit from the ease of growing these algae don’t want to share the pure cultures.  I have also had unscrupulous companies sell contaminated cultures. It is easier to find a few common species, but for the more desirable species, it can be an uphill, ongoing quest. Your best bet is to get a start from one of your local reef club members. If you want to try the less common ones, I have found Algagen to be reliable. I also have goggled for shrimp hatcheries and found seawaterexpress.com. A bit of coaxing with the owner and he turned me on to a very nice brown alga.

Preventing Contamination: Bacterial, fungal and protozoan contamination can cause a culture to be greatly decreased in density and can eventually cause the alga to die. I make every attempt to keep a each culture as “sterile” as possible, knowing that what is considered sterile technique can never be achieved in a hobbyists home.  When I start a new culture vessel, it has been disinfected with a thorough scrubbing. I use one of the growing bottles to inoculate the new vessel. At that point, I cover the vessel and do not open it until it has bloomed. Then, I check it with my microscope, and if it looks clean, I use it to inoculate the next vessel. At that point, what is left is harvested for my zooplankton cultures and to feed my reef.

There is a thought that a protozoan can be removed from a culture by using a micron sieve, if the protozoa is smaller or larger than the alga.

Overlooked Algae: Underused algae, in my opinion. I have found pelagic diatom cultures, (like Chaetocerous being my favorite) to be one of the best algae groups to culture and as a food source, unparalleled. I have had the best growth in my copepod cultures using these easily cultured algae, and my reef tanks have literally exploded with tiny zooplankton. Also, the pelagic alga will compete with the benthic, thus creating an environment that is hostile to the brown covering that mark the cycling of a new tank.

My next quest is to find a culture of the dinoflagulate that is found inside our corals, the zooxanthellae. It is being cultured by research facilities and, I am sure, some of the companies that make products to rock our captive reefs! Imagine being able to place a bleached coral in a solution of symbiotic alga, ready to absorb the organism that will assure it’s survival. I am wondering if we would be able to make a brown coral purple by the alga it is fed?

Because it is so easy.....