New family to fish, new FW community tank

[Familyfishny]

Hello, we are a small family that has started trying to keep fish over the last few months. We currently have 3 Cory catfish of a muted grey (green or bronze, maybe?), five assorted guppies, and one plecostomus of undetermined species. 37 gallon tank, heater (79-80), plant media substrate, live plants, waterfall filter and bubble wall. API master test kit, Water parameters:
Ammonia 0
Nitrite 0
Nitrate between 5 and 10
pH: 7.8

Tank is cycled, but we’ve only had the fish a few weeks.

Issues: we lost two guppies this morning, one with fin rot and the other with loss of floatation/ swim bladder issue. Our previously exuberant corys are subdued and potentially covered in a fine brown film? Their fins look entire. Given the fin rot, a white dot on a guppy fin, and the sad Cory’s, I started a course of API fin & body cure (doxycycline hyclate) tonight, and am wondering if that’s a good idea. We also turned down the heater a bit, which had drifted up to 80.

We’re also struggling with how much to feed them, as the cories seem like they take a while to eat but the guppies will gorge as long as they physically can. Any advice from the experienced fish keepers on the forum would be most welcome.

Oh, and I fished two baby guppies out this morning and stuck them is the so-recently vacated hospital tank. How much food do they need?

Photos: potentially sick corys, orange tail potential fin rot victim (RIP), potentially over fed other guppies.

 

[CaptainBarnicles]

Hello and welcome aboard!

The best cure for fin rot is fresh clean water. How much and how often are you doing water changes?

 

[connorlindeman]

Hello and Welcome!

 

[Familyfishny]

Thank you for the kind welcome! I have been doing ~10% water changes weekly, with gentle substrate vacuuming once or twice a week. I'm happy to adjust based on your recommendations.

 

[CaptainBarnicles]

I've replied in your other post

 

[Slaphppy7]

Welcome to TFF

 

[Byron]

Welcome to TFF. Diagnosing disease or issues with fish is difficult if not to say usually impossible. But given the extreme connection between a fish and its aquatic environment, there are some steps one can take regardless because the effect is only positive. One is substantial water changes. Regularly, if no "issues" are present, a change of 50-70% of the tank volume once a week is normal. Do a good digging into the gravel with the water changer. And keep the filter free of sludge. As long as the parameters of the tank water and the tap water are reasonably the same, you cannot change too much water. Parameters refer to GH (general hardness), pH and temperature. Slightly cooler water is OK, even recommended, as it invigorates the fish. I have regularly seen spawning activity the early morning following a water change.

Do not be quick to think "x" problem, and start adding some cure to the water. These can do more harm than good and even affect healthy fish. Observe the fish carefully, sitting without moving for an hour or longer...once the fish forget you are there, their minds will be off of you and getting fed, and physical interactions will or should be easy to spot, and may tell you a lot about this and that.

I will say that the gravel substrate is not helping the cories. They need inert soft sand so they can sift feed as nature intends. And equally important , gravel holds more dangerous bacterial issues than sand and as the cories are on the substrate so much this can cause serious issues. The roughness is one thing (does not seem bad here), but the bacteria in the gravel is much more serious.

 

[biofish]

Guppies are a bit of a hit and miss. Some people call them hardy but in my experience they seem a bit more delicate and can go down fast. Often times guppies from stores are horrendously overbred so the best way to get longer living guppies is to breed them yourself; breed male from store x and females from store y and z, etc.

And cories are happiest in groups of at least 6! Friendship is power!

as for feeding, I would recommend a smaller pinch of flakes released UNDER the surface of the water. This creates a cloud so the while the guppies can chase after bits, there’s always some that fall to the substrate and give the cories/pleco a chance. Pleco’s are usually nocturnal so you could shift your feeding times to a few minutes before lights out.