Brooks

I was hoping someone here could give me the benefit of their experience with tropical fish, in particular corys.

I have had two of them die in the past week. It is a relatively new tank (Chistmas gift) and only 18 gallons, and has cycled. I used to have a 25 gallon tank years ago, so have some experience with the extensive trial and error that can come with setting up a new tank. I'll give you some info, re: the tank enviromment, etc:

Other fish - 3 glowlight tetras, 3 zebra danios, two platys (don't know what kind, but they seem a little aggressive toward each other and the other fish, and are food hogs.) There are no remaining corys. Using the 1 -inch per gallon guideline, I figure I had 16-17 inches of fish in there, which is at the top limit.

Environment/filters - mechanical filter hanging on back of tank, underground biofilter all seem to be running well. Water is crystal clear and maintains a temp of somewhere between 78-81 degrees. Small, efficient heater rated for up to 20 gallons. Seems ok.

No live plants.

The corys seemed healthy when I brought them home and did well for the first five days or so. I did wonder if they weren't getting enough food because the other fish got it first, but sadly I did nothing about this. Also, I watched for any signs that the platys were harassing the corys, never saw it though the platys are pushy. However, the day before each cory died I found it resting up in the corner of the tank, behind the heater, actually touching it. (this was the top end of the heater, which did not feel warm to my touch). The following day, each cory died in the space of about three hours. Could they have burned themselves or caused some internal damage, or did they starve?

I know these questions aren't easy to answer without seeing the tank/fish, but your thoughts are appreciated. My first impulse to give the platys away, both because they are the two largest fish in the tank, and they are a little aggressive. I do not know the sex of the two platys, that didn't come up when I bought them and I didn't know to ask.

And it seems from what I've read here that I should have 5-6 of each of the danios and tetras. Is that right?

thanks again,

Brooks Waldhart

jim55379

I think it's a little too hot possibly. I would set the heater at about 76 degrees. It's possible that they starved also but I don't think they were burned by the heater. The water dissipates the heat even if they touch it I don't think they could be burned. When I first started out I made the mistake of putting in some angel fish with the goldfish. This is wrong for 2 reasons. goldfish need to be by themselves and they prefer a cooler temp around 19 celsius where the angel like about 25. My goldfish were very agressive eaters and I don't think they allowed any food to be left over or eaten by the angels. I don't know what else may have killed them. I never had any corey's but hopefully this will help you. Maybe the moderator can add something later.

Marc

I have no idea what may be the cause of this.. I keep Corydoras at 82 degrees so heat shouldn't be a problem.. and I seriously doubt they starved.. fish can usually last a few days without food without suffering too badly..

One of my Corys died, though, for no real reason... perhaps they just die randomly, or perhaps it just never acclimated totally.

atmmachine816

my grandpa always had problems getting corys to live but he always succeeded but the heat is not the problem and the platy should be at a 1-2 ratio 2 beeing femals and 1 being male so the femals dont get harrased and yes tetras and danios like to be in groups of at least 6 so a thing you might want to do is decide which of the three fish you want get rid of the other two and get more of the one you want then get 5 or so corys and make sure you have some sinking catfish wafers on hand in case the corys arent getting enougth food and i am assuming you dont have sand as you have an undergravel filter but if you can you should get rid of that as they can cause problems down the road

have anymore question just ask and myself or somebody else can help

jes28

Hi

You dont say what you fed them, I usually give my bottom feeders pellets/tablets that sink to the bottom.

atmmachine816

i dont they do fine with food that falls to the bottom

newbie101

You're overfeeding if you have enough food falling to the bottom for your cories

fish_r_friend

i have pellet food that i put in some tank water so that they sink and my cories really like them

atmmachine816

no i am not overfeeding them i have such strong surfuce movemnet with my filter and bubble wall that a lot of food falls to the bottom

any ideas on how to make more food stay floating

newbie101

oh ok
try cutting a "ring" from a plastic cup and set it in the water away from the filter, then put the food in there
or if the ring is getting tossed around too there are feeding rings that attach to the glass with a suction cup

atmmachine816

ya i tried that and they wouldnt eat from the feeding ring

newbie101

hmm...

vin

First, your corys will not starve within 3 days. Second, what is your water condition? (pH, ammonia, etc) They do not like harsh water conditions. (stay pH between 6.8-7.2) Your temp may be a little too high. They do prefer a cooler temp. I keep mine between 76-78 degrees.....They actually prefer it a bit cooler, but they are happy with what I've got the heater set at so I haven't changed it at all.

Next, when feeding try turning the flow of your filter down. There should be an adjustment knob where the intake tube turns into the tub. I turn mine to low for feeding and back up to medium-low a little while later. Most of the flake food stays afloat long enough for the fish to eat it before it sinks. What little does sink the corys eat but I supplement them with bottom food anyway.

I feed my corys sinking brine shrimp pellets. They absolutely love them. They also like the algae wafers I supplement all of the fish with. I give 1/4 tablet each week.

Butterfly

Your tank could still be going through the cycling process, sometimes it takes awhile. corys don't do well in a cycling or fairly new tank.
Even though they are bottom feeders, the gravel still has to be kept very clean for them.
If you are concerned about them not getting enough to eat, feeding after lights out is a good idea. This gives tehm a better chance of getting a bite before the other fish
If you could test your water and post the readings(Ammonia, Nitrites, Nitrates) maybe
we could help a little more
Carol

Brooks

Thank you to everyone who took the time to field my questions about corys - I will take some readings in the tank and try again in a week or two - perhaps remove the 2 platys in the meantime. Thanks again!