Various fish species have been crossbred over the years either as pure research or as a matter of routine for aquaculture purposes. In order for cross-breeding to succeed, parent fish have to be somewhat closely related.

A few examples:

• tiger muskellunge -- a hybrid between muskellunge and northern pike
• hybrid striped bass -- cross between white bass and striped bass
• tiger trout -- hybrid between brook trout and brown trout
• splake -- hybrid between lake trout and brook trout
• saugeye -- hybrid between walleye and sauger
• hybrid sunfish -- cross between two sunfish species such as pumpkinseed and redear sunfish

There are advantages and disadvantages to use of hybrids. Most grow faster (hybrid vigor) than either parent, but some do not fare as well in regards to survival from egg through fry stage. Most are incapable of reproduction, which is often viewed as an advantage. Some are more fitting to certain types of habitat than one of the parents, and some may have better catchability (in terms of angling) than one of the parents.

It is legal to propagate approved hybrid species. Some species are prohibited from being possessed, transported, sold, etc. in Pennsylvania. For others, we do not permit aquaculture operations with such unless said fish are included on permits issued by the PA Department of Agriculture or raised in a closed system. 

For the aquarium hobbyist working on species that are not native to PA, it is legal to raise hybrid fish, as long as the fish and progeny are NOT released into waters of the Commonwealth anywhere in the state. Further, it is illegal to introduce a species into a watershed where it doesn't already exist.

There are also regulations for specific species where it is unlawful to sell, offer for sale, purchase, possess, introduce, import or transport. Some commonly known species include northern snakehead, black carp, silver carp, bighead carp, round goby, tubenose goby, European Rudd, and grass carp/triploid grass carp (unless by permits authorized by the Commission). To assemble a comprehensive list of all species forbidden would be a major undertaking as possibly any species in the world would have to be included, just remember it is illegal to introduce a species into a watershed where it doesn't already exist.

Tiger Trout

Commission trout hatcheries have been experimenting with raising a small number of tiger trout over the last couple of years to determine if they would grow any faster or more efficiently than other species.

Thus far we have not seen any advantage of raising tiger trout. The experiments have produced several thousand tigers each year and a few are put in with loads of brook trout to be stocked throughout the Commonwealth.

Although biologically possible, wild tiger trout are extremely rare.