Lion and Puffer death

[Darbyy7]

I have a 55 gallon (I plan on upgrading soon once these fish get bigger) aggressive tank with a dwarf lion, who ive had for about 2 months, volitan, fumanchu, and snowflake eel, one month, and a spiky puffer, around 2 weeks. The eel, volitan, drawf, and puffer eat good, silversides and krill, and occasionally ghost shimp which is what the funmanchu will only eat.

Over the past couple weeks, the dwarf has been hanging upside down a lot but will swim fine too. His color was just a little bit lighter. This week he has been hanging upside down more and more lately so I have beginning to think something is wrong with him.
The puffer has been completely fine and hasn't messed with or poked at any of the other fish at all.
My parents, who don't know much about about fish at all, have been feeding them every day (they won't listen to me when I tell them they don't need to eat everyday) which I know is too much for predators, especially since they don't eat the left over food, except for the eel. I did a water change last week so the water shouldn't be too bad though.

Today when I got home, the dwarf was laying on his side on the bottom and the puffer right next to him kind of on him, both dead.

Im wondering what couldv'e caused both to die on the same day, practically on top of each other. I get that the water quatially might have had something to do with it, but does anyone have any other ideas, like maybe if the puffer bothered the lion when it was dying and the lion poked him? Or any other thoughts besides water quality would be useful. Thank you!

 

[reefergeorge]

It is normal for dwarf lions to hang upside down, and was the puffer a spiny burr fish or a porcupine puffer? If it was a burr fish, that is a near impossible fish to keep long term without regularly treating for internal parasites.

 

[namxas]

How large are all those fish, and how large were the dead specimens?

Did you QT the puffer?

Which dwarf lion did you have? A fuzzy? A zebra? If it was a zebra, IME, they tend to be a bit touchy for some reason.

Did the fish have spots? Were they "gilling"? Were the fish off their feed? Were the lion's fins ragged? Have you changed anything in the tank?

It could have been too much food. Your folks need to understand that lionfish can actually eat themselves sick. Additionally, if the food was "off", it may have begun to decay in the fish's GI tract.

Not much info to go on, I'm afraid.

BTW, you might consider backing off on the krill and adding some other foods into your fishs' diets...a diet high in krill isn't good for them.