chaetoceros sp. phytoplankton

Planoi · #1 04/02/2002, 11:40 AM

Hi Doc,

A lfs here has begun offering a live culture of diatom - chaetoceros sp.

Are these diatoms any different than those that build up on the surface in our aquarium? Are they nutritionally beneficial enough to be considered appropriate "tank food" (in comparison to DT's Nannochloropsis) ?

thanks.

MattBeaman · #2 04/02/2002, 11:49 AM

Planoi

If cultured correctly, this species has a nice balance of EFA's and so is used particularly in growing shrimps and clams. It's main difference to Nanno, is as a diatom it has a silicate exoskeleton, and therefore requires a different nutrient solution to culture it.

I am aware that Dr Ron doesn't believe that Chaetoceros is that beneficial, as it has 'hairs' which he thinks will cause it to be rejected by many creatures (especially clams).

As this is still very much a developmental area of our hobby,I personally am still researching the matter, and looking to run some experiments here in the UK. (no disrespect to Dr Ron.)

Cheers

rshimek · #3 04/02/2002, 09:39 PM

Hi Win,

Chaetoceros species are planktonic diatoms that shaped decidedly different from the common ones found on the walls of aquaria. They float, in part through the action of long spines off of each end of the rectangular or cylindrical frustrule (shell).

Probably about 30 years ago, these were tried as experimental foods in the culturing of a lot of invertebrates, mostly larvae, also some clams. They were found to be excellent foods, except for one minor problem. Nothing seems to want to, or is really able to, harvest them well. In clams, for example, they get sucked out of suspension, bound into mucus on the clams' gills, and ejected from the clam as "pseudofeces." Basically, they are too inedible to eat.

As Matt indicates some hobbyists are interested using these algae for feeding animals. In doing this, they are largely re-inventing the wheel, although I suppose somebody will start marketing these algae anyway.

I wouldn't bother with them. There are many other cultured algae which will be better for the phytoplankton feeding animals.

MattBeaman · #4 04/03/2002, 04:14 AM

Ron

I'm starting to agree with you, when trying to find out why this species is fed, there seems to be a lot of .... well.......because......

What I do know is i've seen a growth explosion in my Clam since feeding live Nanno in particular. Though he seems to like dead Tetra too. I've been documenting the growth in photos. He's added 3mm of shell since the 20th March, and 4 'blades' on his top edge which though very thin measure upto 10mm!!

He also packed on about 35 mm in the previous three months.That seems like a lot of growth to me, but I have very little experience with them. What do you think?

Incidentally nitrates are undetectable (well highest was 0.2mg after feeding once) with any kit i've tried at highest resolutions. (salifert, merc etc.)

Cheers

Planoi · #5 04/03/2002, 06:49 AM

Unfortunately Chaetoceros is the only live culture phytos available to the hobby here in Thailand at the moment

Given this situation, do you think it would be worthwhile at all?

So I just wondered what kind of organism eats this diatom?

rshimek · #6 04/03/2002, 07:11 AM

Quote:

Originally posted by Planoi

Hi Win,

Unfortunately Chaetoceros is the only live culture phytos available to the hobby here in Thailand at the moment Given this situation, do you think it would be worthwhile at all?

I wouldn't bother.

So I just wondered what kind of organism eats this diatom?

Large (rice-grain sized) pelagic copepods will crush them and eat them.

MattBeaman · #7 04/03/2002, 07:50 AM

Win

Try Florida Aqua Farms for a mail order algal plate of Nannochloropsis. Don't bother with liquid cultures. The plates though will keep for upto 6months if kept dark and cool, so they should survive the postal system ok. They certainly reach the UK from Florida o.k anyhow.

They're also IMHO the easiest and most reliable way of starting a new culture.

Hope this helps

Planoi · #8 04/03/2002, 08:39 AM

Thanks Matt, Although I believe that Nannochloropsis is probably available somewhere

But going as far as culturing it is a bit too much for me

I have thought about it, but really don't know how to go about culturing.

Ron-

If those larger copepods would eat then is it not beneficial to add it to the tank? Since the copepod themselves and the larvae can serve as food for others...

rshimek · #9 04/03/2002, 09:24 AM

Hi Win,

Well, if it was possible to keep the copepods they would be good food. However, they have never been kept in culture....

Most of the smaller bugs we have in our reef tanks will ignore it, and that means it will just go to foul the water.

Planoi · #10 04/03/2002, 12:04 PM

Quote:

Originally posted by rshimek
Hi Win,

Well, if it was possible to keep the copepods they would be good food. However, they have never been kept in culture....

I meant those that reside in the average tank. Could this diatom could possibly serve as a good food source for the larger size copepod poppulation. How about the bigger amphipod in our tank, are they capable of eating this diatom?

thanks.

rshimek · #11 04/04/2002, 11:05 AM

Quote:

Originally posted by Planoi

Hi Win,

I meant those that reside in the average tank. Could this diatom could possibly serve as a good food source for the larger size copepod poppulation.

No, they don't eat this sort of thing. They scrape other diatoms and bacteria off of surfaces.

How about the bigger amphipod in our tank, are they capable of eating this diatom?

Capable possibly, would they, no. They eat other things.

This diatom is NOT a food that most aquarium animals will eat.