The present invention is concerned with a long-term feed for aquatic animals and especially for fish, shrimp and invertebrates, wherein the feed is stable for an extended time in fresh and sea water and can also be used as weekend and holiday feed for ornamental fish.
Long-term feeds for ornamental fish, i.e., so-called feed blocks or feed stones, are known which have only a very small proportion of organic materials and mainly consist of calcium sulphate. DE 37 07 032 discloses a holiday feed which overcomes the long-term stabilization problems of the calcium sulphate feed blocks through the use of cement and crude rubber. A disadvantage thereof is the fact that the last-mentioned necessary additive materials are almost indigestable for aquatic animals and, in many countries, are not permitted according to the foodstuff laws.
It is an object of the present invention to provide an industrially producable, long-term feed for aquatic animals and especially for fish, shrimps and invertebrates, which feed is stable for an extended time and continuously provides ornamental fish with nutrients. The feed of the present invention can be used in fresh and sea water and is especially useful for warm and cold water ornamental fish without thereby making use of adjuvant materials which are not permitted in certain countries according to food-stuff laws but at the same time, however, does not impair the quality of aquarium water due to other adjuvant materials.
Surprisingly, we have now found that, by means of the use of polysaccharides, for example of plant gums, the use of cement, calcium sulphate and/or latex can be avoided in the preparation of the feed. Additional properties which are substantially improved in comparison with the feeding agents described in DE 37 07 032 are also included in the present invention
Thus, according to the present invention, there is provided a long-term feed for aquatic animals, especially fish, shrimps and invertebrates in fresh and sea water. The feed is stable for an extended time., is insoluble, does not load the water chemistry in fresh and sea water and can also be used as a weekend or holiday feed for warm and cold water ornamental fish. The feed contains 1 to 50% by weight of a plant gum, preferred agar-agar. Preferred is a feed for ornamental fish which contains 1-10% plant gum, most preferred 2.9%. Typical plant gums which may be used are, for example, carrageenan, agar-agar, gum arabic, tragacanth, karaya gum, ghatti gum, carob bean meal, tara gum and/or xanthans. Preferably, the plant gum is agar-agar.