do clowns eat phytoplankton?

[cyclgrl]

I put a capful of DT into my tank about once a week after the lights go out.

Tonight, I sat there watching my tank for a little while afterwards. To my amazement, my clown was darting back and forth exactly the way I've seen other fish go after brine shrimp. Was he eating phytoplankton? I thought that was for filter-feeders only.

[Gary Majchrzak]

I raised a larval Amphiprion frenatus {Tomato Clownfish} past metamorphosis in a 10 gallon tank of greenwater {Nanochloropsis} with no Rotifers or other supplemental feedings, so judging from my personal observations, I'd say yes- Anemonefish do consume phytoplankton.
However, I believe your adult Clownfish might have been going after Mysid shrimp that smelled the phyto treat- or other zooplankton that appeared after the lights went out.

[BonsaiNut]

Hey Gary -

Tell me more about your greenwater experience. I have often wondered about trying it, but had heard that the high nutrient level required for proper phyto cultures would be bad for the larva. It would certainly simplify larval rearing - toss the larva into a pool of greenwater, and add rotifers at the same time. The rotifer culture would probably peak just about when the larva were mature enough to really want to eat them :) Did your clowns appear to "thrive" in the greenwater? Have you had other clown raising experience and if so, how would you compare the greenwater experience with the other (rotifer or whatever) experience?

As an aside, I have raised brine shrimp to adulthood in greenwater with no additional nutrients. However, as adults the brine shrimp were very pale in color (though I could not detect any other difference in size, appearance, etc). My fish ate them just as fast either way :)

Thanks for any comments!

[Gary Majchrzak]

BonsaiNut- Well, my greenwater experience all began in the backwoods of Tennessee.....{j/k!}:p
Actually, what happened was a mistake. Somehow a 10 gallon vat of my greenwater got contaminated with Amphiprion larvae. How many- I'll never know. {If Rotifers had contaminated this container, they would have consumed the dense Nanochloropsis culture.}
When I drained the very 'thick' greenwater, {it was like pea soup}, I was quite shocked to find a vividly colored newly metamorphosed Tomato Clownfish in it !
The coloration on that fish was very remarkable. {I don't usually name fish, but I called this one 'Tiger'!}
I can't comment on the survival rates of Rotifer vs. Greenwater only fed Amphiprion larvae. My experience was highly uncontrolled. But I doubt the larvae I'm referring to could have possibly seen any other prey items in that 10 gallon aquarium full of greenwater.

[BonsaiNut]

Very interesting! What nutrients were you using in the greenwater? What was the basic salt mix? What other factors - what was your lighting, circulation, etc?

Though I am not raising clowns atm, I am interested in finding that "holy grail" of larval fish farmers - a prepared food solution that will allow larval fish to metamorphosis without any additional feeding work being required on the part of the breeder.

In addition, I also have a hypothesis I would like to test about the impact of lighting on color development of juvenile clowns. In my experience, clowns color up very differently under intense lighting versus dim "standard" flourescent lighting, and it is something I would like to explore further.

When you say the little juvenile was "vividly colored" was it a brilliant "natural" coloration?

Finally, I laugh when you say your 10 gallon was "contaminated" with a fish larva :) The same thing happened with me and the brine shrimp. I assume that some brine shrimp eggs got into my greenwater culture via cross-use of airline tubing. At any rate, I had some VERY dark phyto cultures in a rack by a window (receiving direct sunlight) when I saw something swimming :) It turned out I had about 8 or 10 small brine shrimp in the culture. I let them go (out of curiosity) and they got quite large (as large, if not larger, than brine raised via other methods). After they matured, they were eating the phyto faster than it was reproducing, because the culture became progressively lighter until they had pretty much cleared it out. At that point the shrimp went into the reef for the final 2 seconds of their lives :) This was all happening in a clear 2 liter soda bottle (my culture vessel of choice).

[Gary Majchrzak]

My greenwater cocktail was made up of sterilized {microwaved} RO water and Instant Ocean salt mix, Florida Aqua-Farms Micro Algae Grow formula and Nanochloropsis.
The 10 gallon vat of it was illiuminated with a 20" fluorescent GE plant grow light. Circulation was provided by the HEATER. {Warm water rises.}
"Tiger" was much more brilliant in natural coloration than all of my other Rotifer raised Clownfish.

[BonsaiNut]

Very very interesting...

You now have me going :) It is something I am going to have to try :) In this day and age of digital photography I would love to set up some "experiments" and share the results with other reefers.

Last question - how warm did you keep the water (in general?)

[Gary Majchrzak]

Quite honestly I don't know the answer to that final question. Those were very cheap and inaccurate heaters and thermometers I was using on that greenwater setup. All of this was located in a warm basement. I would say the minimum temperature was 80 degrees F.
I always ran my main reef at 75-76 degrees back then, and the greenwater was definitely warmer to the touch than the main tank.
It's too bad I didn't take many pictures back then {1994-95-96}, either.