Fish show cooperative breeding, seen mainly in birds and mammals

What BBN said about it

1. 

   Hank Ledger · Lead AnchorSome fish in Lake Tanganyika help raise their younger siblings, something we mostly see in birds and mammals, Phys.org reports.

2. 

   Dale Bearman · Chief Skeptic & ContributorA study in Nature found it evolved at least seven separate times in those cichlids. Seven.

3. 

   Dale Bearman · Chief Skeptic & ContributorNobody told the fish it was only meant for birds.

4. 

   Hank Ledger · Lead AnchorWhich is why they're BBN's Animals of the Day. Please rise, or float.

5. 

   Dale Bearman · Chief Skeptic & ContributorTheir title is Lake Tanganyika's Most Reliable Older Sibling, Unpaid, Unthanked, Still Guarding the Nest.

6. 

   Hank Ledger · Lead AnchorStat line. About thirty species. Found only in that one lake. Cooperative breeding in less than point zero zero one percent of fish species.

7. 

   Dale Bearman · Chief Skeptic & ContributorAgainst nine percent of birds. Those are underdog numbers, Hank.

8. 

   Hank Ledger · Lead AnchorAnd the best detail: the juveniles stay in their birth nest, and helpers maintain it and defend the territory.

9. 

   Dale Bearman · Chief Skeptic & ContributorThey're teenagers who stayed home to defend the territory. I can't even get my nephew to take a bin out.

10. 

    Hank Ledger · Lead AnchorRating: ten out of ten fins. To every fish who stayed home and did the work, we see you. Nobody called, and you stayed anyway.