Sick minnows... fin rot/body necrosis? How to clean tank?

[youaremyjoy]

Hi...

I have been working on a new tank, starting from scratch and was using some $0.15 minnows to help get it cycled. This is week 2. I started with 4 of these rosy red minnows in a 15 gal tank. Now that they have all died, I want to make sure that I'm not passing anything along to the next crop. I would like to know (if possible) if this might be something infectious that I need to strip the rest of tank down and clean - gravel, decor, treat/toss live plants. I know that the stress of cycling the tank, etc is a huge contributor to fish disease - originally thought this looked like fin rot and tried to treat as such from reading the posts here.
I still need to finish the cycle so I can eventually develop a small community tank, so suggestions on how to proceed are much appreciated!



1~What type of fish is afflicted? In addition, please describe what is wrong with the fish to the best of your ability (i.e. cotton like growth, bloated, etc.).
Rosy red minnows
Starts with loss of tail fin, then body flesh starts turning white.
Progresses to loss of pectoral fins.
Fish die within 48-72 hrs of showing signs.

2~What are your tank parameters (ammonia, nitrites, nitrates, temp, pH)? Please give exact values.
Ammonia/nitrites/nitrates all 0, using API master test kit. Temp 76-78F. pH 6.8

3~ How large is the tank? How long has the tank been set up?
15 gal, 2 weeks into cycling.
Using some Eheim ceramic media from established tank at trusted LFS to help.

4~What type of filtration are you using? Please give the name and number (i.e. Fluval 304) and amount of gph if known.
Tetra whisper 20 filter

5~How many fish are in the tank? What kinds of fish are they and what are their current sizes?
currently 0, there were 4 fish, rosy red minnows, less than an inch in length

6~When is the last time you did a water change and vacuum the gravel? How often do you do this? How much water do you remove at a time?
Changed water 15-25% daily, added API stress coat and quick start with each change.

7~How long have you had the fish? If the fish is new, how did you acclimate it/them?
2 weeks.
Floated in bag in tank for a 60-90 minutes, added tank water to bag water, then netted fish into tank.
Did not add bag water to tank.

8~Have you added anything new to the tank--decor, new dechlorinator, new substrate, etc.?
All new substrate and decor, (rinsed prior to adding), new live plants (cleaned prior to adding)

9~What kind of food have you been feeding your fish, have you changed their diet recently?
TetraMin Tropical flakes

 

[anteatergoanna]

Gosh, those poor fish. Did you try treating them with fin rot meds?


Sent from anteatergoanna's burrow

 

[youaremyjoy]

yes...
partial water changes
treated tank with antibiotics and melafix (had kanamycin on hand, removed charcoal from filter)
Cut back on feeding by 50%
Was in the process of getting some salt to add, but was too late

 

[Delapool]

Nasty bacterial infection there

Very likely still present in the water but normally healthy fish wouldn't be bothered by it. Some massive tank water changes may knock it down before adding more fish.

I've found it worthwhile changing to a different school of fish. I've lost tetras to similar, restocked, lost fish, given up and changed to a different fish type that did ok.

 

[youaremyjoy]

Thanks for the reply. Do you think treating the water with the kanamycin would be worthwhile?
I do have some KMNO4 that I could use to dip the plants and decor.


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[Delapool]

Just checking but tank is empty now?

It's too hard for me to get here and too expensive so I would go with several 80% pwc's to try and flush it out. I'd suggest one or two anyway.

But if cheap for you there or here if it was getting close to expiry date I would. Bacteria can easily last in an empty tank for a month so a long time to wait out.

Either way I would say you are just cleaning the water. If conditions favour infection again it will unfortunately come back.

Your readings for water specs look ok, I'd also be looking at a different lfs/hardy fish type just in case you got a bad batch. Or go fish less cycle.