Aquarium plankton – mistakes in the use of phytoplankton supplement

Phytoplankton in the tank

Let’s now see how we can supplement the algae component and its benefits.

The right question to ask should be “does it make sense to add phytoplankton in the tank?” and then “how to add it?”

Fitoplancton in batteria

The answer to the first question in my opinion should always be YES, because this plankton type is at the base of any trophic level of the oceans.

It is more complex to answer the second question. The best way to supplement phytoplankton is by having a live product available, not buffered and with a good diversity of organisms.

Alive: it is a product that can grow and breed in the tank, it is definitely the less troubling solution regardless of the type of system you use to manage your tank.

Macro Acropora sp. polyps

Not buffered: commercial products can stay on shelves for several months or years, they will contain preservatives, and even if in small quantities they will have an effect on the phytoplankton cell. Once poured in the tank they will degrade quickly and become pollutants, immediately reversing the desired effect.

Diversity of organisms: phytoplankton is made up of microalgae with different nutritional values like the vegetables we eat. Several studies today are carried on to define a nutritional value ideal for sea bream larvae, clams and other aquatic organisms for human consumption, in order to eventually increase productivity and decrease nutritional deficiencies during growth.

Macro Acropora sp. polyps

One of the major problems our tanks face is the high oligotrophy needed to maintain SPS corals in good health (and nice colours). We equip ourselves with protein skimmers and everything else that can help us reduce the organic waste produced by fishes in a quick and efficient way.

These accessories only imitate the role of a sponge, a bivalve, a Gorgonia which filtrate water by keeping what they need to survive. So far it doesn’t look like this paragraph has anything to do with phytoplankton supplementation in the tank. But phytoplankton is just one type of the particles which a sponge, a bivalve or Gorgonia would keep for themselves!

Phytoplankton supplements will increase your sponge population, contributing to the clearness of the water and to maintain the health of the zooplankton present in good quality live rocks!

Common mistakes with phytoplankton

A common misunderstanding which I have been facing in the past months is that of many aquarium enthusiasts who use phytoplankton (which is a good starting point) thinking they are directly feeding the SPS coral polyps.

The coral polyp is not able to predate on a single phytoplankton cell, firstly because of its “vegetarian” nature, secondly because of its very small size, which is usually around 20 um (0.02 mm) with a great deal of variation towards the smaller spectrum, one example is that of Nannochloropsis sp. with a cell size of 1×2 um (0.001×0.002 mm). In addition we can also argue that the nematocyst present on the tentacle, once used, has to be completely replaced by a new one. This means that the animal is using up a resource in terms of energy which has to be outbalanced by the captured prey in order to make sense.

In the following article we will go through the nutritional characteristics of the most commonly cultured phytoplankton genera to be maintained using simple equipment. Later on we will show you the zooplankotn genus and their developing times.

[Article written by Davide Mascazzini]

Related articles:

  1. The global seas nutrient cycle: a better understanding of its application in aquariums
  2. Plankton – zooplankton and phytoplankton – getting to know them
  3. Phytoplankton – algae species, cultures and results
  4. Aquarium plankton – mistakes in the use of phytoplankton supplement


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