KEEPING LIVING FOOD ALIVE 



i 



WILLIAM T. IMMES 



No fish culturist ever seems to have as 

 much storage space for living foods as he 

 would like. The best practice, therefore, 

 is to utilize available space to the utmost 

 advantage. This is not always done, as 

 is shown by the fact that many breeders 

 gather live food daily, even in cool 

 weather, when it keeps well if given half 

 a chance. 



To a great extent the keeping of 

 Daphnia and of fishes works on the same 

 general principles. Both breathe the free 

 oxygen in the water. This is renewed by 

 absorption from the atmosphere, and by 

 aquatic plants. For Daphnia it is not 

 practicable to replenish the oxygen by 

 plants, because they would be disturbed 

 too often ; hence we must depend upon 

 absorption from the air. The tanks 

 need not be deep — three inches of water 

 is plenty. The writer uses two inches 

 with good success. However, as large a 

 surface area as possible should be pro- 

 vided. The amateur is often quite limited 

 as to space, but as a rule he could use 

 what he has to a better advantage. For 

 instance : If a space will permit the use of 

 a tank measuring three by four feet, the 

 usual plan is to have it about sixteen to 

 eighteen inches deep. Far more efficiency 

 could be had by using several trays four 

 inches deep, stacked in a pile and sep- 

 arated by about seven inches. According 

 to the observations of the writer, Daphnia 

 survive better in shallow than deep water. 

 Many are slightly injured in catching and 

 are unable to swim near the surface. 

 These sink to the bottom, where the in- 

 creased water pressure lessens their 

 chances of survival. 



Another important point is to keep all 



living food cool, especially Daphnia. Cool 

 water holds more oxygen than warm, and 

 it also slows down the life actions of the 

 animals, which then make less demand 

 on the available supply of oxygen. Meth- 

 ods of keeping the water cool can be best 

 decided in individual cases, but it is cer- 

 tain that direct sunshine should be en- 

 tirely excluded in warm weather, and also 



Calico Telescope Goldfish 

 Photo by F. Schaefer 



that a draft should be maintained over the 

 water's surface. 



Owing to their small size, it is difficult 

 to supply Daphnia with running water, as 

 they would be carried away in any ordi- 

 nary overflow. Several large wicks of 

 thick felt carried over the edge of the 

 tank, and allowed to hang outside to a 

 length of several inches will carry away 

 enough water to allow a constant drip 

 from a faucet to strike on the water sur- 

 face. 



An important point is to remove at 

 once all insect enemies that have unavoid- 

 ably been taken when catching the 

 Daphnia in the pond. These feed raven- 



