Aquí hay gato encerrado
Polenta stumped a lot of you with her "Santa María qué pinta tiene esa niña."
I have something similar but a little easier. What do hispanohablantes mean when they say "Aquí hay gato encerrado."

6 Answers
There is something fishy going on.
Hay algo sospechoso pasando.
¿Quién tiene gato? ¿Sabe alguien encerrarlo?
De vez en cuando el mío se llama Changó se escapa de la casa y suele esconderse bajo mi coche en la calle. Siempre es el mío nunca escoge otro. Antes yo solía huirlo con una escoba y me costaba mucho tiempo y frustración. Luego el señor Vang, vecino mío, sugirió otro táctico: una bolsa de papel y paciencia. Sencillo, me dice. Abre la bolsa con estrépito, ponla cerca del coche y espera. Apenas pasan 30 segundos y el gato se precipita desde su escondite para meterse en la bolsa. ¡Buen consejo, señor Vang!
Who has a cat? Do you know how to capture him?
From time to time mine, he's called Changó, gets out of the house and customarily hides under my car in the street. It's always my car, nobody else's. Before I used to use a broom to shoo him, and it cost a lot of time and frustration. Then my neighbor, Mr. Vang, suggested another tactic: a paper bag and patience. "Simple", he says to me. "Open the bag making lots of noise, put it near the car, and wait." Barely 30 seconds go by and the cat scurries out from his hiding place right into the bag. Good advice, Mr. Vang!
Aquí hay gato encerrado. = Theres something fishy going on here.
or
I smell a rat (huelo una rata),
Alguien que está diciendo lo obvio.
Someone who is stating the obvious.
Hello!
This link from 2013 might be the answer to your question. "Hay gato encerrado"
Hope this helps.
Regards!
UPDATE: After more than 24 hours of this posting, fishy in Spanish is sospechoso. Here are the English/Spanish translations.
- there's something fishy about him - hay algo en él que resulta sospechoso
- it sounds fishy to me - me huele a chamusquina (informal); (Spain)
- there's something fishy going on here - aquí hay gato encerrado; me huele a chamusquina (informal); (Spain)
Before I look at the link, I'll guess something like "You have a tiger by the tail" meaning you've got a tricky or dangerous situation that could go very wrong if you make a wrong move.