r/freshwateraquarium

We have 40 gallon freshwater tank this morning I ended up finding 3 dead fish and I don't know why. Before we had ammonia spikes and that explains stuff but today I checked the water and it's was normal levels. We're new at this hobby and try our best to get everything right idk what happened here. In the second picture the Cory looks like it been nipped on or something I'm not sure. We use to have 3 Bettas 2 females and one male and we watch them make sure there were no nips or aggressive behaviors we've been good for months we've added a lot of plants for hiding spots and 2 big pieces of driftwood and they were getting along fine until last weekend our male betta looked like he got jumped and basically all of his fins got nipped and he was still alive when we found him and we put him in a 5 gallon tank to try to heal but he didn't survive then a few days later we found of our other betta female dead as well and she had eggs and it's just looked like she got nipped up too and her belly looked like it got eaten out we figured it was our koi betta since she was the biggest but as you can see in the picture she's passed from something and we can't tell what her eyes were looking a little cloudy yesterday night and she didn't wanna eat bloodworms and then today this morning she's dead . Any advice please would help us greatly we don't want to killing our fish.

EDIT: would like to include the fishes I have in this tank we have a 6 cories 1 otocinclus and 2 snails one nerite snail and one rabbit snail. I also texted my fish guy and he callede and let me know that based on the pictures (I sent him the same pictures I posted) that they gotten beaten up on and that it could've been the oto I would like to know if maybe anyone else would share that opinion. Reasoning that the oto just gets bored and starts killing 😔 I would hope that's not the case.

Got my first aquarium started up in February and I’ve really enjoyed getting into the hobby. Over the past couple of weeks I’ve started to get algae developing on driftwood, rocks, substrate, and plants. I’m not too worried about it in some places because I know it’s natural, but I don’t want it to strangle my plants and don’t want as much on the substrate itself (this is actually a pretty light covering on substrate as I just vacuumed it).

I’ve played with my light settings a lot, vacuumed, and done water changes, but haven’t had a lot of luck getting it off of the plants. I also have a bristlenose pleco, but it’s still growing and hasn’t made much of a difference on surfaces yet. I got some shrimp the other day, but I can no longer find any of them and can only assume they became midnight snacks for my gouramis.

Can anyone give me some advice on helping to limit the algae on plants and substrate? Is there anything obvious I’m missing?

Um, is this good? I got neocaradina shrimp
Tank has been cycling for a month by now.
And a few shrimp passed away due to failed molts.

Hi,

This is a bit of a vent, sorry— it’s really sad for me to say, but I think that I may have to unfortunately say goodbye to my two bettas, Rogue and Blue.

My school’s staff got them in the spring of 2025, after asking me and me telling them not to. In December of 2025, I decided I couldn’t stand seeing them like that and spent hundreds of dollars setting up 10 gallon fish tanks for each of them. I’ve watched them go from faded and sad to energetic and full of personality, and they have become something that motivates me to stay on track. I planned to bring them to college with me this fall.

Unfortunately, the security head here has told the center director that the heater and filter are not necessary, and are dangerous because they are not connected to GFCI outlets. I told the school I’d be willing to buy the outlet materials if the warehouse could switch them out, but he refused. He said the tanks needed to go, and that betta fish did not need to be in a tank that big.

I told him they need to be in a 5-10 gallon tank, and he said “no they don’t”. I told him they also needed 76-78 F water, and he also said they did not. He tried asking me what the PH I was running was, when I answered him 7.6-7.8, he told me there was plenty that he could ask that I didn’t know, and that he had fish tanks too. He told me a couple months ago that he knows they dont need that, because he had a friend who fought bettas and the guy “just kept them in cups that werent heated” and “they were fine.”

I told him I had nowhere to bring them, and would rather put them down or something if they wouldn’t let me keep the tanks. He said they’d “figure something out”, but I know that he will put them back in a little vase like the ones they used to be in, everyone keeps insisting it’s fine for them.

I don’t know what to do. I don’t want to return them to a pet store. I don’t have friends I trust to care for them. I could put them in my bathroom, but they’ll throw a fit about that too.

What should I do? Put them in vases again? Put them down so they don’t have to go through that? Give them to someone to take? Idk what to do.

Original post: https://www.reddit.com/r/freshwateraquarium/s/Y8VPkpWhsp

What first seemed to be cute kuhli behavior now feels like a dark omen. I am now experiencing mass tank casualties and am desperate to fix whatever problem this could be. My plants appear to be dying, there is sediment coating/flying around everywhere. Tank is kept at 80f and is heavily planted. I feed using vibra bites and algae wafers

5/14: suspicious death of an adult yoyo loach and mystery snail. Both found at the top of the tank and passed away overnight. All water parameters normal (ph6.8, 0 ammonia/nitrite, 5 nitrates). Did a 20% water change immediately after finding and chalked it up to murder suicide

5/15: added 3 panda corys and 2 albino corys to tank

5/19: Found a dead panda Cory, albino Cory, and juvenile neon tetra. Albino was torn in half and panda was floating at top. Tetra was dead on bottom. Tank parameters still normal (ph.6.8, 10-20 nitrates, 0 ammonia/nitrite) another 20% water change.

5/20. 1 adult neon tetra dies. I go to the aquarium store to have my water tested professionally and discover slightly high phosphates and a ph of 6.6. Nitrates are at 20ppm and 0 ammonia/nitrites.

Recommended to:
add sponge filter and new plant that will help lower phosphates
feed less (they are fat)
Remove dying plants

5/21. 1 juvenile neon tetra dies

After thorough investigation of the surviving fish, it appears as though my betta has holes in her head. She has had a tumor for months that continues to grow on her tail. All the other fish appear to be normal. I took a picture of one albino Corycat that could suggest ich, but when looking at it through the naked eye it looks like 2 shiny spots. I will post pictures in the comments.

I have lost 28% of my tank at this point and wake up every day to a new dead fish. What can I do to stop this nightmare???

First and foremost, please don’t hate because I have a basic tank lol trying to convince the husband to let me livin’ the tank up.

But!! I think I just caught my OB zebras, Stripe and Koi, mating!!

Lots of questions, sorry if this is all over the place!

I am the owner of a betta tank at home, and a friend is going to give me a 1.5 gallon tank so that I can put some plants and possibly a couple of shrimp in there! With that being said, I’m pretty sure I’ll need to get a small filter, fluval stratum, and a grow light (won’t be near a window).

I’m trying to spend as little money as possible on this, while of course prioritizing the health and comfort of the shrimpies, so I’m looking for any other necessities/suggestions! What kind of plants do they thrive with? Preferably low maintenance as I’m new to aquatic plants.

Is there a cheaper or “generic” version of fluval stratum? Or is that brand top notch?

Water is very hard where I live, will the plants soften the water enough for the shrimp to survive?

Do we think anything in the current photo could be reused? Not sure if you’re supposed to put something on top of the stratum.

Would a couple of snails be okay in there if I have a lid? Any and all information would be much appreciated.

TIA :)

I've had this tank for probably close to a year now and it's been nothing but constant problems. All was fine until I went on a week long vacation in November and had someone inexperienced look after it while I was gone.

They overfed my recovering pet store betta and he unfortunately passed not long after.

Then all of my other fish slowly fell ill and died to some kind of white, fuzzy infection I could never quite identify. So I decided to make this a shrimp tank. Now, almost all my shrimp are covered in vorticella and I just feel so defeated I'm not sure how to proceed.

I know there's salt dips but it seems like a massively widespread infection, so picking out all the shrimp to individually salt dip sounds tedious. I previously went through a gauntlet of treatments to try and make sure whatever killed my fish had died. I'm worried about hurting my snails with any more treatments, I have bladder snails and a mystery snail.

I did melafix, completed that treatment then did kanaplex, and right now I have some Expel-F dissolving in the water because I figured it was fungal before realizing it was definitely vorticella.

Water parameters: pH 7.6 temp 75-80° ammonia 0 nitrite 0 nitrate 40-80. I do weekly 40% water changes (4 gallons of the 10 gallon) and squeeze out the sponge for the filter every time to ensure it's flowing properly.

What in the world am I doing wrong? Is my temp off? Do I need to do more frequent water changes? Why does this seem so hard?

right above the airstone all these bubbles staying at the top and won’t disperse? i’ve had the airstone liek 3 months it’s never done this does anyone know what’s going on or why

In my scaped vase

I got this tank a couple months ago and recently moved and had to set it up again. is there anything that looks like it needs improving?

got this little dude at petco today because my boyfriend loved him so i had to have him in my tank. the petco i go to usually has very knowledgable employees theyre very helpful. except i was told my new dumbo guppy is a female. after looking into it a little i dont think it is. anyway this is charizard. am i right is he a dude? or is he a dudette?

First time seeing this in my tank. Just want to make sure it’s not harmful!

Update: looks like this is “slime mold” and it’s very sought after! Proud to home this guy. I will add updated in the comments for those interested!