Went away for weekend to find 3 dead fish in my tank?

Question

I came back tonight to find that my Silver tip Shark and my 2 Zebra L/F Danios dead. My dad said he fed them at 3:00 pm every day but i am not sure i believe him. I am looking for more ideas of why!!! they died but not my other fish. (1 neon tetra, fiddler crab, 8 guppies, 3 harlequin rasbora ) other info : 29 gal tank , ave temp 78 degrees

Answer 1

i think your water tank is too small for your 1 neon tetra, fiddler crab, 8 guppies, 3 harlequin rasbora and the fishes that died.. how long have u using ur tank? maube ur dad overfeed the fishes

Answer 2

Take a test for everything. Then do a 50% water change thst could be the problem the cycle. Have you just started up. But maybe too much food has over balanced the cycle. Do a 50% water change and if the fish are still dying it could be a disease.  

Answer 3

They wouldn't have died of starvation in a few days, so don't be down on your dad!

Answer 4

How are you water levels?(ammonia, nitrate, nitrites).  Is it possible he over fed the fish?

*EDIT*

Feel free to contact me with more details, I would be happy to help you.

*Second Edit*

If you do a water change do not do a 50% change, that is very drastic and should only be done in emergencies(such as an overdose of ich medication).  a 10-15% water change every 3-4 days would be best if you think theres an issue with your cycle.