According to Icelandic news today. Fish has been dying in Kleifarvatn lake. But Kleifarvatn lake is inside Krísuvík volcano system. The exact reason why the fish is dying is not known at this point. But report suggests that large amount of fish has been seen dead already. I do not know how much fish there is in Kleifarvatn lake.
This suggests that hydro-thermal and hot spring activity in increasing in the lake. This also suggest that increased toxic levels (for the fish) are now changing in the lake. What toxins are at work here I do not know. But it can be assumed that it is what comes with magma.
For the past three to four years. Krísuvík volcano has been inflating and deflating at regular time intervals. What this means in unclear at present time. But this is signs of increased activity in the volcano anyway. Hydro-thermal and hot spring activity has also been increasing during this period. This has also been followed by increased earthquake activity in Krísuvík volcano when inflation takes place. What happens next is impossible to know for sure. But it is clear that Krísuvík volcano is still far away from erupting any time soon.
Icelandic news about this