I think fish must live in warm and tropical waters. Because these fish are near human body temperature. In my opinion O.niloticus is a good opinion.

thank you

This reply is coming very late, but it seems extremely unlikely that Sars CoV2 will be able to infect fish. Nevertheless, if you're experimentally inclined and really interested in this question, there are many fish cell lines that can be easily obtained from major culture collections. Unless you have a BSL3/PC3 lab, you won't be able to try to infect these cell lines with Sars CoV2 itself, but as a starting point you could at least ask if a pseudotyped virus containing the Sars CoV2 spike glycoprotein could enter fish cells. There aren't many infectious clones available for fish viruses that you could use as a backbone, but perhaps IHNV could work? Article Recovery of NV Knockout Infectious Hematopoietic Necrosis Vi...

thank you

It appears that fish may not be affected. Mammals however may be the main the animals affected and primary vectors.

Very topical question. I have heard of those who are doing research on this. I will contact them. Then I will try to answer you. Because my special in botany

Not sure of the preprint is available yet, but there's this...

Cooke, S.J., W.M. Twardek, A.J. Lynch, I.G. Cowx, J.D. Olden, S. Funge-Smith, K. Lorenzen, R. Arlinghaus, Y. Chen, O.L.F. Weyl, E.A. Nyboer, P.S. Pompeu, S.M. Carlson, J.D. Koehn, A.C. Pinder, R. Raghavan, S. Phang, A.A. Koning, W.W. Taylor, D. Bartley and J.R. Britton.  In Press.  A global perspective on the influence of the COVID-19 pandemic on freshwater fish biodiversity.  Biological Conservation.  00:000-000.

The connectivity of COVID-19 and Aquatic resources is very important. In the case of the spread of the disease, if water is involved, this will be a big problem. The reason is that in many countries, fish is considered the main food (soup).