Rotifers as first discus food

[samir]

here's a cut and paste that has me interested.
Rotifers: An Alternative First Food
by Dougall Stewart on www.cichlid-forum.com
Yolk feed versus Rotifers

Lim and Wong (1997) demonstrated that in dwarf gouramis, a species known for its micro-fry, that during first food feeding, rotifer fed fry grew up to 33% faster and in addition they have a 44% greater survival rate compared to yolk fed cohorts.

Parent reared versus rotifer fed

Lim and Wong performed a second experiment which compared parental reared larvae growth and survival rates to rotifer fed larvae growth and survival rates.

Lim & Wong’s Method

* Brown discus larvae that were obtained from a 18 month old male and a 14 month old female. The time to hatching was 60 hours, post fertilisation, at 28-30 °C and 20 % water changes were carried out on all tanks every 2 days

* On the second day after hatching, all the fry except for 20 which were left with the parents’, were removed from the tank. 20 of the removed fry were placed into a 20 litre aquarium, and a further 30 fry were placed into a 30 litre aquarium

* The fry that were left with their parents, fed from their body slime. The others were fed on rotifers at a rate of 5-6 ml per litre from day 4 to day 7

* Between days 8 and 14 the larvae in all of the tanks were fed solely on Artemia nauplii

* 20% of the tank water was changed every other day throughout the experiment

The results

* Survival rate:

* Parent reared 85%
* Artificially reared, 20 liter tank 95%
* Artificially reared, 30 liter tank 70%

* Size and Shape:

* Significantly less variation in overall size in both of the artificially reared tanks, compared to those that were parent reared
* Similar sizes fry by the end of day 14 in all tanks

[marg]

Samir,

That is a really interesting article.

So where do you get these little critters from?

Marg.

[samir]

i'm trying to find out, will let you know as soon as i do

[dino]

Rotifers are multicellular aquatic organisms. They are about 1/4 the size of newly hatched brine shrimp - so can be used as the first food source for fish fry. They are essential for raising marine fish fry. You can find out how to culture rotifers on the marine aquarium forums. Rotifers are usually not needed for breeding FW fish as their frys are generally large enough to feed on newly hatched brine shrimps (or powdered food or boiled egg yolk).

This information is based on what I've read on the marine fish forum - I have a pair of clown fish, but they have not spawn yet.

[samir]

Rotifers are usually not needed for breeding FW fish as their frys are generally large enough to feed on newly hatched brine shrimps (or powdered food or boiled egg yolk).


* The fry that were left with their parents, fed from their body slime. The others were fed on rotifers at a rate of 5-6 ml per litre from day 4 to day 7
* Between days 8 and 14 the larvae in all of the tanks were fed solely on Artemia nauplii

boiled egg/powdered is messy, i'm talking about the first few days after free swimming. egg yolk has a pretty bad survival rate.
maybe brilliant has another way, RO injections or something.

[dino]

Rotifers are usually not needed for breeding FW fish as their frys are generally large enough to feed on newly hatched brine shrimps (or powdered food or boiled egg yolk).

I was just refering to FW fish fry in general and not specifically to discus. I have no experience with breeding discus, but have gathered that discus frys are pretty small and rely on the parents' slime as the first food source.

My guess is that rotifer culture may be successful is because it is high in protein and small enough for the new fry to swallow, and would not foul the water like boiled egg yolk would.

[samir]

i didn't mean you were wrong. its just that egg yolk and powdered food really create a mess. anyways anybody know where to get rotifer cysts from ??? the freshwater ones.

[Robdog]

In most LFS these days they seem to have those little plastic fridges on the counters that have portions of blackworms and BS in little blue "poppers". I've sometimes seen rotifers available but it must be an issue of supply and demand. I've heard they are mainly used in marine tanks or are these a different type?

[samir]

Rob there are both marine and freshwater rotifers, I guess the freshwater would be easier to cultivate, they feed on algae, one of the sites i read said they can reproduce into billion in a couple of weeks. i did see the frozen blister packs, apparently they are also freeze dried. i'll do a trial and error with my next spawn and let everyone know what happens. i'm trying to get a culture or cysts, once i get that i'll get the fish to spawn and see how it goes.