Grundsjöröding (Salvelinus alpinus) belongs to the salmon fish, Salmonidae. Unique. Threatened, protection host. Separate species of char, genetically related to the 'large char' in the Vättern, among others. Later immigrated than char in the Swedish mountain chain for approx. 7 000 years ago.
The trout stocks in the western part of the Långå Fishing Area have their origins in the ground-sea trout unique to Långåfishing. Som framgår av namnet är dess hemvist i de sedan av början 1970-talet reglerade Grundsjöarna. By regulating the lakes, Grundsjömagasinet was formed, which can be compared to a 'battery'’ with potential energy that can be converted into electricity in the Långå power plant. But also with significance for electricity production in other power plants downstream of Långå in Ljusnan.

The life cycle of ground sea trout matches the life of other salmonids, activities and behaviors. Sport fishing for char starts already before Christmas and at the turn of the year, as soon as the ice wears, to culminate in the spring ice, sometimes right into May. Pimple fishing for char with a stick and some kind of bait is very popular with magical experiences in the spring sun.
Barbless hooks must be used so that the fish can be released without serious damage. Common baits are leaf worms or maggots. When the fish is lifted over the edge of the ice, there is always a risk that its delicate eyes will be damaged in the cold air and drafts. Fisk, which should not be retained, is therefore carefully unhooked in the ice hole and 'backed'’ back down under the sea ice.
Pimpelfiske, so-called vertical fishing, after charring can also be done from a boat in summer. Pimple fishing can almost be seen as an entertaining fishing within household fishing. Several fishery conservation associations organize pimpel competitions with attractive prizes for competitors.

The char is usually an elusive fish. The char is nocturnal and its circadian rhythm controls its foraging. The char in the Långå fishery behaves 'pelagic', that is, in the open, still water, often over bottoms where it grazes, among other things, on Arctic Ocean relics such as shrimps and merles of Mysis Relicta and Pallasea Quadrispinosa. This is a guide for choosing flies and nymphs. In the evening, char gather in shoals and swim along the shores. Pole fishing for char from a boat can be done by harling fishing.

For Grundsjö char in Grundsjön, an unconditional limit of a maximum of three char per day applies. Chars caught in excess of three must be released unharmed. This also applies to damaged char (in addition to three catch fish) which are euthanized and re-released.