Performance of Co-Housed Neon Tetras (Paracheirodon innesi) and Glowlight Rasboras (Trigonostigma hengeli) Fed Commercial Flakes and Lyophilized Natural Food

Abstract

Little to no research has been conducted thus far regarding aquarium fish nutrition. In order to ensure the welfare of house-kept ornamentals, such studies should take into account that there are distinct biological differences occurring between different fish species/taxa, especially in regard to the structure of their digestive organs. Accordingly, a 12-week trial was executed to assess the effects of two commercial flakes and a mix of lyophilized natural food on the condition of co-reared neon tetras, Paracheirodon innesi (Characidae), and glowlight rasboras, Trigonostigma hengeli (Danionidae). The four feeding groups were as follows: (T)—Tetra flakes; (O)—Omega flakes; (TO)—Tetra + Omega; (TOL)—Tetra + Omega + Lyophilizate (twice a week). There were no differences in final body weight (FBW) between the feeding groups of either species, but in the case of neon tetras, FBW increased significantly from the initial value only for the T group. However, histological observations and measurements of digestive organs (livers, intestines) showed pronounced differences between the two species. The supplementation with natural food in group TOL caused lipoid hepatic degeneration only in the rasboras. The healthiest histological structure of livers and longest intestinal folds were found in group T of the tetras and group TO of the rasboras. Whole-mount staining for bone and cartilage did not reveal any significant deformities or differences in terms of bone mineralization. In conclusion, it was outlined that concurrent feeding of co-housed, anatomically diverse ornamental fish species is a highly ambiguous task, because the nutritional strategy applied for a community tank may yield radically divergent effects, most of which may remain unnoticed when depending only on external body observations and measurements. Most emphatically, this was highlighted in regard to the dietary supplementation with natural food—although no significant effects were observed in neon tetras, severe lipoid liver degeneration occurred in glowlight rasboras.

Comparative Morphology of the Digestive Tract of African Bush Fish (Ctenopoma acutirostre) and Paradise Fish (Macropodus opercularis) Inhabiting Asian and African Freshwaters

“…For fish and aquatic animals with extremely varied food-acquisition strategies, knowledge of the structure of the digestive tract is particularly important and allows subsequent research into the physiology of this system. Such knowledge can help avoid feeding and welfare problems, which often occur during fish breeding in home aquaria [ 3 , 25 ].…”

Sustainable Aquaculture: Nutrition Studies in Early Developing Finfish, Ornamentals and Experimental Model Fish

“…Kasprzak et al [ 7 ] contributed to the welfare of house-kept ornamentals with a 12-week trial to assess the effects of two commercial flakes and a mix of lyophilized natural food on the condition of co-reared ornamental neon tetras ( Paracheirodon innesi ) and glowlight rasboras ( Trigonostigma hengeli ). Histological observations and measurements of digestive organs showed pronounced differences between the two species, with severe lipoid liver degeneration in glowlight rasboras fed on the natural food.…”