In my experience very few shops ever sell daphnia. Why not just catch your own? Most fresh water bodies have regular blooms of daphnia, particularly during winter months when lower water temperatures mean that the oxygen levels are higher. Rain also washes nutrients, such as waterbird droppings, into lakes and ponds, and this results in bacterial blooms. The preferred food for most cladocerans is bacteria, and when bacteria (usually coliforms) bloom, so do the daphnia, which will also consume single-celled alga, if bacteria are in low numbers.
At the moment daphnia are blooming in Lake Monger, and all it takes to catch them is a long-handled, reasonably fine net. Catches will yield a plethora of different sized organisms, which can be easily screened in order to feed appropriate sizes according to needs.
Just bear in mind that if feeding wild-caught daphnia and other such live foods to very small fishes, that there are organisms that feed on daphnia which will also attack fish fry, and these need to be carefully excluded; a simple procedure if the catch is placed into a white bowl or such, and potential pests removed with a pipette, baster or such.
One thing to bear in mind is that if there are very large numbers of daphnia present in lakes, it is wise to not be greedy and attempt to overcrowd your catch in buckets. They have high oxygen requirements, and overcrowding will result in most or all of the organisms dying before you get to feed them to your fishes.
Syd.
By the way, forget the harbingers of doom who claim that live foods carry diseases. Every aquarium has microbes that potentially cause disease, and live foods seldom, if ever, introduce anything nastier than already in the aquarium.
In 63 years of feeding wild-caught live food, I have never had any problem with introducing disease into my aquaria.
Edited by sydad, 20 August 2015 - 10:41 AM.
inside my fry tank, should I be able to just keep some daphnia in there without Feeding them too much? (I have fairly green water) I have heaps of algae in the water to feed the daphnia, but if they breed and reproduce won't the small Daphnia (babies) be able to fit through the netting? (it's about 0.5 mm then swim around the tank, then the fry in the tank would eat them! Almost an infinite food source, and when there are too many Daphnia in the trap/box I could just release them in to the tank a keep a couple left to start again! Would this work? Please help!!!
