To clean a
sponge filter first of all you unclip the plastic parts and slide the tube of sponge off.
I don’t find it necessary to rinse the sponge very often at all . After a month or more the bucket of old water will be dark brown. Yes you can rinse it once a fortnight or once every two months. We are not cleaning the sponge as much as just removing the bigger chunks of old uneaten food. Some fish poop will find its way into a sponge filter but most poop actually settles on the substrate just under the sponge. They are great for biological filtration but not so good at mechanical. Good to house bacteria not so good at picking up poop. A simple vacuum every fortnight will be enough to remove poop from the substrate.
Some thoughts on breeding CPDs.
An extremely small fry that is difficult to see let alone provide the small amounts of food.
I would recommend a
green water tank to raise the fry but you and the students will not easily see fry in green water. I am serious about using a green water tank.
A rainbow fish fry at 7 o’clock in this picture.
A tank sitting outside growing a green water culture of floating algae and well basically fresh water plankton ( microscopic bugs) . Used to add more food to indoor tanks.
No smell at all with this culture of micro living food.
Option two .
In order to be able to see baby fish( fry) you could feed Infusorea. For the first 4 or 5 weeks the fry are to small to eat live baby brine and don’t easily learn to eat dry dust / dry
fish food as small as talcum powder.
Infusorea is a culture of micro creatures that you grow by the millions on rotting plant material and rotting vegetables. It really really really stinks and needs to be cultured outside. Or in a shed perhaps?
Option three.
The natural way.
The tank is left uncleaned . Algae grows on a mass of dead and living plant material. The tank is full of plants and actually looks nice in a wild way. Infusorea in small amounts will grow without smell . The fry will find food . This would be the easiest way and would look the best.
A tank on the floor with as much old plant material as you can find. Fish eggs are on the plants and all it takes is no adult fish and time. This at least looks nice in a wild sort of way? Multiple tanks ( containers) are used to jump the adults away.
More food.
In addition to the above foods is vinegar eels.
Not really a complete food but an additional food source.
My experience suggests getting a few fry is easy enough Feeding them until big enough to eat baby brine or start on dry food is not easy.
A few will do it without your doing anything if there are no adults around and the tank is established / ( dirty)
In short .
#1 Green water tank.
#2 An established tank full of plants without adult fish.
#3 Stinking Infusorea.
There are tons of u tube videos on the subject.
I honestly think jumping all the adults into new tanks every fortnight is your best choice. It will require 3 tanks. In the real world a bucket is a tank . A plastic tub is also a tank but is not a aesthetically pleasing to look at.
Start by building the colonies of bacteria ON the new filter.
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