Upgraded filter to fluval 107 and killed fished
II have a heavily planted 20-gallon long with 5 pea puffers and 5 otocinclus and amanos. The tank has been established for several months and everything was doing great before I upgraded my filtration.
I replaced my HOB filter with a canister filter. I rinsed all of the new parts, reused some of my old filter sponge inside the canister to preserve beneficial bacteria, and moved the biological media over. Around the same time, my town was doing sewer/street work, so I’m also wondering if something got into the tap water during a water change.
Since the filter change, all of the fish have been acting “off.”
The progression has been:
First couple of days: glass surfing and swimming frantically.
Then: rapid breathing and hanging near the surface.
Now: they’re mostly lethargic, swimming oddly and bumping into stuff. Not eating.
One puffer and one otocinclus died. The others still haven’t eaten in days.
Here’s what I’ve tried:
Several water changes, (purchased spring water in case tap water was contaminated from construction)
Added an airstone and increased surface agitation.
Turned off my co2
Tested the water multiple times.
Current parameters:
Ammonia: 0
Nitrite: 0
Nitrate: 0
pH: 7.0–7.5
GH: ~130 ppm
KH: 40–80 ppm
Even with the extra aeration, the fish still aren’t acting normally. My CO₂ drop checker had been blue for days after I shut the system off, so I don’t think excess CO₂ is the issue.
One thing that makes me suspicious is that there were a lot of new plastic parts involved in the canister setup (tubing, spray bar, fittings, etc.). Could manufacturing residue or something from cutting the tubing be causing this even after rinsing everything? Or does this sound more like some type of contaminant that got into the water during the municipal sewer work?
Any thoughts would help.