Why do my Neon Tetras and Otocinclus often die?

[martinmin]

Hi, I have neon tetras and octcinclus in my little fish tank, about 4 and 8 gallons. They often die a few days, although plants grow well. Parameters should be ok, because plants like them. 

What are typical reasons for Neon Tetras and Octcinclus die in small planted fish tanks?

 

 

[Milliardo Peacecraft]

I've always have had issues with keeping neon tetras and they never have seemed to last.  I've always just assumed some of my other fish decided they looked like sushi, though I've never seen them really terrorized.  As of the Otos, those have been challenging in the past, but my luck has been way better since I started using the Rapshy super greens food.  I've had outstanding luck with otos since using that.  My conclusion is that there wasn't enough algee long term to keep the Otos happy.

[Colu]

When you say parameters should be ok have you tested for ammonia nitrite nitrate pH 

[Sarina]

Neon tetras and otocinclus are both fish that heavily rely on consistent water parameters. In small aquariums, it becomes more difficult to maintain consistent parameters due to the small water volume. I actually don't recommend either of these species for an aquarium smaller than 10 gallons just because it is incredibly difficult to keep them healthy in anything smaller. 

Plants can thrive in a variety of conditions that can be detrimental to fish, so just because your plants are healthy does not mean that the environment is ideal for certain species of fish. Testing your water is going to be a good place to start. 

[Galabar]

Plants can enjoy water parameters that would kill fish.  You should test...

[JettsPapa]

Neon tetras seem to be much more fragile than in years past.  It's probably either weak genetics or the conditions they're raised in, or a combination of the two.

It's my understanding that otocinclus for sale are all, or almost all, wild caught.  They often go too long without eating between being caught and reaching your aquarium, which can cause irreparable harm to their digestive systems.  If that hasn't happened they're just about bullet proof.  I bought three several years ago.  Two died within a day or two.  I took them back and the store replaced them.  Those two (or one of those and the original) died within another day or two.  I didn't try again.  The one survivor is still alive (or at least was several days ago), despite being moved at least twice.

[martinmin]

On 7/17/2023 at 11:52 AM, Colu said:

When you say parameters should be ok have you tested for ammonia nitrite nitrate pH 

Yes. I did. That is not a problem.

On 7/17/2023 at 12:00 PM, Sarina said:

Neon tetras and otocinclus are both fish that heavily rely on consistent water parameters. In small aquariums, it becomes more difficult to maintain consistent parameters due to the small water volume. I actually don't recommend either of these species for an aquarium smaller than 10 gallons just because it is incredibly difficult to keep them healthy in anything smaller. 

Plants can thrive in a variety of conditions that can be detrimental to fish, so just because your plants are healthy does not mean that the environment is ideal for certain species of fish. Testing your water is going to be a good place to start. 

Then what fish do you recommend for small tanks? Just plants are not good.

[martinmin]

On 7/17/2023 at 12:54 PM, JettsPapa said:

Neon tetras seem to be much more fragile than in years past.  It's probably either weak genetics or the conditions they're raised in, or a combination of the two.

It's my understanding that otocinclus for sale are all, or almost all, wild caught.  They often go too long without eating between being caught and reaching your aquarium, which can cause irreparable harm to their digestive systems.  If that hasn't happened they're just about bullet proof.  I bought three several years ago.  Two died within a day or two.  I took them back and the store replaced them.  Those two (or one of those and the original) died within another day or two.  I didn't try again.  The one survivor is still alive (or at least was several days ago), despite being moved at least twice.

I moved otocinclus to a big tank, which has more thin algae on the glass, and looks like they are all eating, so probably it's because of no food in the small tank. And water parameters are also cause, because one time the same day I bought otocinclus, and change water for the tank, and the next day, they all died in that tank. I didn't test water for the existing water and the water in that tank.

On 7/17/2023 at 11:47 AM, Milliardo Peacecraft said:

I've always have had issues with keeping neon tetras and they never have seemed to last.  I've always just assumed some of my other fish decided they looked like sushi, though I've never seen them really terrorized.  As of the Otos, those have been challenging in the past, but my luck has been way better since I started using the Rapshy super greens food.  I've had outstanding luck with otos since using that.  My conclusion is that there wasn't enough algee long term to keep the Otos happy.

Probably that's true: "My conclusion is that there wasn't enough algee long term to keep the Otos happy."

[PineSong]

There isn’t enough algae in most tanks for otocinclus to survive, in my experience. I feed mine algae wafers at night when the other fish are asleep so they don’t get outcompeted for food, and I also feed them Soylent Green from Repashy. 

[Sarina]

On 7/19/2023 at 11:05 AM, martinmin said:

Then what fish do you recommend for small tanks? Just plants are not good.

I actually have a list! I'd recommend keeping only 1 species in the 4 gallon, and a minimum of 5 in a group of any of the tetra species. Most small fish will jump, even if they're not known for it, so it's recommended to have a lid. Killifish are well known for jumping, so choosing one of those will definitely require a lid. 

-Least killifish

-Norman's lampeye killifish

-Clown killifish

-Green neon tetra (much hardier and a bit smaller than regular neons, but still very brightly colored!)

-Scarlet Badis

-White cloud mountain minnow

-Any ricefish, there are lots of different colors

-Ember tetras

-Chili rasbora

-Endlers livebearer (male only bachelor tank)

-Celestial pearl danio

-Pygmy corydoras

-Neocaridina shrimp

-Amano shrimp

-Honey gourami

-Betta

[Lennie]

On 7/17/2023 at 9:40 PM, martinmin said:

They often die a few days, although plants grow well. Parameters should be ok, because plants like them. 

This actually does not mean anything. Plants can grow in a tank with ammonia or nitrite present. And keeping small tanks is harder than keeping bigger tanks, as parameters can change or go off very quickly.

Otos like to be in groups and are grazers. I would not keep any otos there as it will be mission impossible to provide a natural food growth nonstop and keep them in a group. And neons are too big for that tank.

In that tank size I would only consider tiny rasboras, a single betta, or shrimp. I personally have to disagree with other options listed in the comment above, considering I am keeping some of the listed ones myself, I don't think many species are not ideal to be kept in that tank size. Decorations, plants, heater, filter, etc. all steal swimming space from the tank. So actually a 5g tank is not a 5g unless you fill it fully and keep it bare. and 8g is not an 8g with the same mentality.

Clown kilis are also small in size but they are territorial in my experience.If you want them maybe get one one male to 3 females in that tank size and def no more than a single male.

Scarlet badis may hide a lot. @Guppysnail may comment on it further. Tiny rasboras can give you great colors in a planted tank as a school, and they are tiny micro predators. Betta is always a good option as long as you meet the requirements as other fish.

[Guppysnail]

I really do not have suggestions as I do not like to keep fish of any type in anything smaller than a 10g. 
I did rehome my least killi fish from a 10g. I found 2 fry hiding after and they went into a 5 gallon. Unfortunately it was a boy and girl so I now have a colony in there. 
I also recently took in a lone black tiger badis. He went in with the LK. 
The more I watch them though I do believe a pair or trio of black tiger badis would do great in a 5 g more so than scarlets. Scarlet boys need space or they fight mercilessly. 
Any badis I have kept Scarlet badis, Badis badis and now tiger badis do not take to commercial food. They will sometimes eat enough just to survive but not enough to really thrive. They prefer worms and will eat live bbs. 
A colony of shrimp with a nerite are great in a 5g. Maybe even a really cool dwarf crayfish though I have not kept those so can’t say if they would be appropriate. 
Anyway back to the least killifish Herterandria formosa, the little group is thriving quite nicely in the 5 g. They are not active and are more retiring and laid back than tetra, rasbora or danio who need lots of swim room to thrive. They are a more relaxed meandering type fish. I keep duckweed and dwarf water lettuce on the surface so I have had no jumpers and it’s been almost a year of them in there. 

[Peaceful Fish]

I prefer White Clouds and Cherry Barbs over the smaller tetras. 

[martinmin]

On 7/21/2023 at 11:16 AM, Sarina said:

I actually have a list! I'd recommend keeping only 1 species in the 4 gallon, and a minimum of 5 in a group of any of the tetra species. Most small fish will jump, even if they're not known for it, so it's recommended to have a lid. Killifish are well known for jumping, so choosing one of those will definitely require a lid. 

-Least killifish

-Norman's lampeye killifish

-Clown killifish

-Green neon tetra (much hardier and a bit smaller than regular neons, but still very brightly colored!)

-Scarlet Badis

-White cloud mountain minnow

-Any ricefish, there are lots of different colors

-Ember tetras

-Chili rasbora

-Endlers livebearer (male only bachelor tank)

-Celestial pearl danio

-Pygmy corydoras

-Neocaridina shrimp

-Amano shrimp

-Honey gourami

-Betta

This is a good list. Thanks.

[reefhugger]

On 7/17/2023 at 3:00 PM, Sarina said:

In small aquariums, it becomes more difficult to maintain consistent parameters due to the small water volume

This statement is so true and so important .  I maintain two larger aquariums ( 55 & 70 gal) and two small ones (15 & 20).  The difference in care and stocking even between the 15 and 20 was noticeable to me in the initial setup and long term maintenance.  If at all possible, an upgrade to a larger tank helps a great deal for you and your fishes and impacts the types and numbers of fish that can be happy and healthy.