Actually, otters are OK too, just maybe not as tasty or common? Other things classified as not meat include amphibians and other semi-aquatic mammals (hippos, if you're brave enough to try to hunt one!). Some of these became more relevant with the christianisation of the Americas.
Also, no meat Fridays haven't been abrogated, although it would be interesting to chart how fishing-related industries have fared in big Catholic countries compared to other countries in the past 60 years. The Vatican made a concession that, subject to local regulations, you could substitute the Friday abstinence for a different penance (e.g. visiting the sick, extra prayers ...), but the no meat option was still the default. It was intended to help people who really had nothing else to eat and where total fasting wouldn't be medically advisable. But they soon found that people interpreted the 'penance of your choice' option as 'don't bother anymore', so the abstinence from meat has been promoted again in some places. In England and Wales (which are a united Catholic jurisdiction, separate from Scotland and Ireland), abstinence from meat has been reintroduced as the universal rule since 2011, to be substituted by another food for those who already don't eat meat.
Aoine, the Irish word for Friday, means 'fasting'. But in Ireland the bishops' conference haven't reinstated obligatory no-meat Fridays, they've just gently hinted that it might be a nice idea on Fridays in Lent. 😁