1. INTRODUCTION  
2. SAMPLE  
2.1. The HI sample of WALLABY detected galaxies in the Eridanus supergroup  
2.2. The optical sample combining the Brough et al. (2006) catalog and Cosmicflows-3 catalog  
3. ANALYSIS  
3.1. Photometry  
3.2. Tidal strength for the HI sample  
3.3. Additional parameters  
4. RESULTS  
4.1. HI asymmetry  
4.2. HI disk size  
4.3. Color profiles  
4.4. Color gradients  
5. DISCUSSION  
5.1. Tidal effects on the distribution of HI  
5.2. Color gradients as a tracer of star formation distributions  
5.3. Other environmental effects  
5.4. Caveats and future perspective  
6. SUMMARY AND CONCLUSION