dinoflagellates the same as diatoms?

[NaCl]

i have a brown coating that spreads over the entire tank
every few days, under the microscope, they are small
brown balls that move. Are these the same thing as
'diatoms'? I ask so that i can get appropriate critters
to consume them. Any suggestions would be appreciated. :)

[ATJ]

Yep, sounds like diatoms. Dinoflagellates have flagella - whip like "tails".

Diatoms are very normal in an aquarium. Most snails, e.g. Turbo and Trochus will eat diatoms.

[rshimek]

Hi,

The picture would appear to show dinoflagellates (sorry Andrew, the flagella would not be visible at that magnification, and most dino's are approximately spherical).

These can be controlled and need to be controlled.... This control needs to consider two factors.

First, proximate control - get something to eat them. Several animals will do this. The best bets are grazing snails, or conchs such as the Strombus maculatus (available from IPSF) or Strombus alatus (Florida fighting conchs) available from several sources. These are not "the end-all," however. Snail control is slow... it goes at a snail's pace.

And it will not solve the problem of reoccurance.

So... second, ultimate control. This would be a longer termed process. The dinoflagellates are there because the nutrient levels in the system are high enough to allow them to thrive. So you have to trap those nutrients and remove them. The most efficient way to do this is to set up a macroalgal growing area in your system and regularly harvest and discard this algae.

This area may be in your main tank, or it may be in your sump, etc., but NUTRIENT EXPORT MUST BE DONE. Otherwise you will have signficant nutrient overload in perpetuity. And that overload will fuel dino blooms....

:frog;

[ATJ]

Dr Ron,
Would temperate and/or sub-tropical Strombus spp. be any good? I know there are a few species found around Sydney and I had some in my tanks many (many!) years ago.

[rshimek]

Hi Andrew,

Subtropical animals might be okay - the Strombus alatus used in some tanks here, including mine, is subtropical and does real well. It depends on the thermal tolerance of the particular species.

:D