Fine granular feeds for fry of fishes and shellfishes capable of remarkably elevating the survival rate of fry, improving the cultivation efficiency, and causing little elution of nitrogen sources therefrom into seawater or water in feeding, which are characterized by containing at least three active components, i.e., (a) a long-chain unsaturated fatty acid calcium salt blend comprising 80% by weight or more of long-chain unsaturated fatty acid calcium salt(s) having at least 18 carbon atoms, (b) 20% by weight or less of a browned matter formed by heating molasses or saccharides, a browned matter formed by heating saccharides with amino acids or a mixture thereof at an arbitrary ratio, and (c) a mixture of peptides obtained by hydrolyzing animal protein, and being in the form of fine grains.
The invention concerns a complete feed composition for fish larvae, characterized in that it has a phospholipid content not less than 8.5 wt. % of dry matter of the feed.
A composition for long term improvement of water quality in biological tank systems is described as: 1) at least one highly or poorly soluble Al.sup.3+, Fe.sup.3+, TiO.sup.2+ or ZrO.sup.2+ salt of an organic carboxylic acid, optionally mixed with an organic carboxylic acid; 2) at least one water soluble N free biologically degradable organic compound; 3) at least one soluble alkali or alkaline earth metal salt of an organic carboxylic acid; and 4) at least one Mg.sup.2+ salt of an organic carboxylic acid, optionally mixed with at least one Ca.sup.2+ of an organic carboxylic acid; and also 5) trace elements and vitamins, particularly water soluble vitamins of the B series. Changes in water quality determining parameters can be reduced, minimized or eliminated by using the described agent and thus a significant reduction in partial water change frequency or a clear extension of periods without water changing can be achieved.
