The study investigated the skin anatomy of snakefish (Erpetoichthys calabaricus) and African catfish (Clarias gariepinus) to elucidate their ecological adaptability to extreme fluctuations in the aquatic environment. E. calabaricus, known for its ability to thrive in both aquatic and terrestrial environments. C. gariepinus, significant in aquaculture and a model for studying environmental toxicity. Though genotypically unrelated, they are potential models for study of adaptation and resilience in water bodies
Histological techniques, including staining with H&E, PAS, MT, and Alcian blue, and morphometric analysis were employed to analyze six samples of adult E. calabaricus and twenty samples of adult Clarias gariepinus
The histological features of the skin of E calabaricus comprise a vascularized hypodermis, a mucous-rich epidermis, and a collagen-rich dermis. C. gariepinus shows distinct regional skin differences. The dorsal skin is thicker, containing keratinocytes, melanocytes, and chromatophores, offering mechanical protection, dark pigmentation, and predator resistance. The ventral skin is thinner, lighter, and rich in mucous cells, aiding in defense against pathogens, gas exchange, and osmoregulation. Additionally, scale pockets observed in the ventral region are thought to assist environmental adaptation.
In summary E calabaricus demonstrates higher ecological resilience with specialized structures for terrestrial and aquatic survival. Layers of epidermal mucous and sensory cells further enhance adaptability by mitigating environmental challenges. Conversely, C. gariepinus exhibits regionalized skin adaptations for turbid aquatic conditions.
The study emphasizes the importance of specifying skin sampling sites to avoid inconsistencies in future research. Both fish have evolved unique structural and functional skin adaptations to their ecological and physiological needs, providing insights into their survival mechanisms across diverse environments.