About the sturddlefish, a hybrid between an American paddlefish and a Russian sturgeon. They can hybridize despite not even being in the same family.
https://www.quantamagazine.org/extra-dna-may-make-unlikely-hybrid-fish-possible-20200805/
https://www.quantamagazine.org/extra-dna-may-make-unlikely-hybrid-fish-possible-20200805/
Quanta Magazine
Extra DNA May Make Unlikely Hybrid Fish Possible
The unintentional creation of “sturddlefish” hybrids may illuminate the genomic mechanisms that govern whether species can interbreed.