Then I felt it—warm, damp air. I dropped my bags and ran.

The heater had failed. I don’t know exactly when. Sometime after I left for my parents’ house, it stopped regulating and just kept heating. The water was over 90 degrees. Everything was dead.

I lost two female bettas I’d had for two years—a koi and a platinum. Six otocinclus. A rescue guppy. A nerite snail.

What I felt

Guilt, mostly. I built that tank. I was supposed to take care of those fish, and I didn’t.

Equipment fails. I checked everything before we left—it all looked fine. We were only gone a few days. But knowing that doesn’t help when you’re staring at a tank full of dead fish.

I’m still processing it.

What I didn’t know

I bought the Hygger heater because it had overheating protection. Digital controller, automatic shutoff at 94°F. I thought that was enough, but it wasn’t.

The built-in thermostat failed. With nothing else monitoring the temperature, it just kept running.

I didn’t know external temperature controllers existed. I wish I’d known that before.

What’s next

I needed to understand what happened. Not just “the heater failed” but why a heater with a built-in thermostat could cook a tank.

I spent hours reading. Forum posts, product reviews, Reddit threads. Thermostats can stick, fail mechanically, or lose calibration. When they do, the heating element keeps running with nothing to stop it.

That’s when I found external temperature controllers. They monitor water temp independently and cut power if something goes wrong.

Inkbird ITC-308S. It’s made for aquariums.

I ordered it and installed it on my 110-gallon the day it arrived. Every tank I run from now on will have one.

Before I rebuild, I’m running a 24-hour leak test. Heat can compromise the silicone seals.

The 40-gallon is getting rebuilt, but not as a fish tank. I’m building a paludarium—half water, half land. Tiered structure with eggcrate and PVC. Lagoon-style aquascape at the bottom with shrimp and inverts. Vivid emersed plants growing out of the top.

I’ve never built one before. I’m reading, watching build videos, planning the structure. Learning how people do this right. External temp controller from day one.

I’ll document the build—what works, what doesn’t, the adjustments along the way. Maybe it helps someone else. Or maybe I just need to write this down.

The tank will run again. I’ll share what I learn.

People always ask what I’m keeping.

The short answer: way more than I planned, and most of it wasn’t bought from a store.

A lot of what I’ve learned came from cross-checking instead of trying to find the correct answer: INJAF for the “treat fish like animals, not decorations” perspective, years of lurking r/Aquariums to see what actually goes wrong in real aquariums, and a lot of random YouTube searches.

The 110-gallon (what’s in it, in plain English)

The guppies in my tank aren’t from PetSmart. They’re generational — descendants of fish I got almost four years ago when I mixed classic guppies with endlers in separate tanks, then combined them and let them breed.

Now I’ve got color combinations I can’t even predict. Some look like fever dreams — neon orange bodies with blue fins, yellow tails with red spots, patterns that make no sense but somehow work.

The 110-gallon. Fish at every level, plants everywhere, and nobody’s killing each other.

The paradise gouramis bred. Three times. In a community tank. I wasn’t trying to breed them — they just did it.

I’ve also got bottom dwellers that mostly hide (plecos, loaches, corys), two pea puffers that haven’t killed anyone yet, and a pearl gourami that turned out more beautiful than I expected.

It’s chaotic. It works. Mostly.

How I ended up with this mix

Almost four years ago I started with guppies and endlers in separate tanks. Eventually combined them and let them breed.

When I got the 110-gallon UNS tank about two years ago, I consolidated everything and started building out the community. My office went from looking like a fish store to looking like I just have one really big tank problem.

I was shooting for an active community tank. Lots of movement at different levels. Fish that wouldn’t tear up my plants.

I thought about goldfish — I kept them briefly in my early 20s — but they uproot everything. I ended up rehoming them to a friend whose kids wanted to get into fishkeeping. Helped her move the tank, passed along supplies, the whole handoff.

My dad built the stand for that setup too, and it’s still one of the most solid pieces of fishkeeping infrastructure I’ve ever owned.

So I went for bottom dwellers (loaches, corys, plecos), mid-level swimmers (guppies), and top/mid-level fish (gouramis). The pea puffers are wildcards but they fit.

Fish that surprised me

Pearl (the pearl gourami)

Pearl now. Hard to believe he was the palest one in the tank when I bought him.

Pearl was pale and washed out when I bought him — sitting in a crowded tank with a bunch of other juvenile pearl gouramis. I almost didn’t get him.

Once he settled into my tank and grew out, his colors came in strong. He’s striking now.

I might’ve thought Pearl was a female when I named him. Once the orange color and long dorsal fin came in, I realized the truth, but by then I'd grown fond of the name.

The paradise gouramis (and the breeding I didn’t ask for)

I underestimated their breeding capabilities. A lot.

A male and female pair managed to hatch eggs on three separate occasions in the community tank. I wasn’t trying to breed them. They just figured it out.

The female has been rehomed because I can’t keep up with demand for baby paradise gouramis. The original male (Frank) is staying. The last batch of juveniles will be my last time with paradise gouramis.

Frank. He figured out how to breed in a community tank three times. I wasn’t even trying.

I was surprised they bred so well in a community setup. No aggression toward Pearl, no issues with anyone. Line-of-sight breaks make a big difference.

The kuhli loaches + nocturnal crew

Most recent additions are the kuhli loaches. I watched the Dune movies and decided I needed my own little “Shai-Hulud” zipping around in the sand.

They’re nocturnal. I barely see them during the day unless I turn on the blue moonlight at night. My lights have a blue setting that makes nighttime viewing easier without blasting them with full light. Worth it.

The plecos are the same way. Bristlenose and clown plecos hide most of the day in their caves.

Night shift.

The pea puffers

I’ve kept pea puffers for years, and some are aggressive while some aren’t. The two in my 110 haven’t caused problems because I keep them fed. I have a self-sustaining colony of Malaysian trumpet snails specifically for them to hunt.

Fed pea puffers are calm. Hungry ones cause problems.

It works in my setup. That doesn’t mean it’ll work in yours.

The mistake I keep making

Overfeeding.

I’ve done it multiple times. You’d think I’d learn, but then I see the fish following me around like dogs and I convince myself they’re actually hungry this time.

They’re not. They just act like it. Fish learn the routine fast — they see me and they run the “feed me” script. And I fall for it anyway.

Last time I overdid it: algae explosion within two weeks. Too much uneaten food breaking down, nitrates spiked, hair algae on everything.

Took a month to get it under control. Reduced feeding, manual removal.

This is where the “contradictory advice” problem gets real. Some people fix algae by blacking out, some dose stuff, some change filters, some swear it’s all light, some swear it’s all nutrients. I’m not trying to win debates — I’m trying to keep a tank stable. For me, the boring answer worked: feed less, remove manually, and stop making huge swings trying to fix it in a weekend.

Now I feed less. Sometimes I skip a day if someone looks chunky. Hard lesson to learn but it matters.

I’ve also dealt with algae outbreaks from too much light, ich a couple times, impulse buying fish without researching compatibility first, and being lazy about water changes when I was running five tanks. Everyone makes mistakes. It’s about how you bounce back.

My dad also handed me a copy of Dr. Axelrod’s Mini-Atlas of Freshwater Aquarium Fishes (mini edition — ridiculous title). It’s old-school, but when you’re drowning in “trust me bro” advice, a printed reference feels grounding.

Fish personalities

All of my fish have favorite sleeping spots. I can always count on them being there when I look.

Some are more anxious, some are more relaxed, but most are just food hogs. They’re each different.

Feeding rotation

I feed once a day. I rotate between:

• Flakes: Fluval Bug Bites Tropical Flakes, Omega One Super Color Flakes

• Pellets (staple): Hikari Tropical Micro Pellets

• Pellets (rotation): New Life Spectrum Thera+A

• Bottom feeders: Hikari Algae Wafers, Omega One Sinking Veggie Rounds

• Frozen (twice a week): bloodworms + brine shrimp (Hikari Bio-Pure / San Francisco Bay)

I drop algae wafers at night sometimes so the nocturnal crew can eat in peace. This also stops the guppies from trying to eat them. Fat little pigs.

Less is best with food. If I notice someone getting chunky, I’ll feed every other day.

Territory and coexistence (and the only “don’t copy me” note)

If you take anything from this post, take this: don’t copy the stock list like it’s a recipe.

Add fish slowly. Watch behavior. Assume personalities will surprise you.

This mix works for me because the tank is heavily planted, there are a ton of sight breaks, and I’m paying attention every day.

If something goes sideways, you need a plan B — spare tank, ability to separate, or willingness to rehome.

The full stocking list

If you’re curious about exact numbers:

Bottom: 1 bristlenose pleco, 1 clown pleco, 8 kuhli loaches (2 normal, 6 black), 10 mixed corydoras (albino, salt and pepper, juli, black Venezuela)
Mid-level: 20+ guppy-endler hybrids (generational), 1 pearl gourami, 2 pea puffers
Top/mid: 1 male paradise gourami (Frank) + juvenile paradise gouramis (looking for homes — Phoenix area if interested)
Cleanup crew: Malaysian trumpet snails everywhere

Almost four years of letting them breed. I have no idea what the next generation will look like.

It’s chaotic. It’s active. And after two years, it’s stable where it counts.

Turns out the tank didn’t give a shit about my $80 filter media.

What actually made things easier wasn’t the gear. It was boring stuff done consistently. Plants. Patience. Not dumping an entire container of flakes in because “they look hungry.”

The reference tank

My main setup is a 110-gallon Ultum Nature Systems rimless. Freshwater planted community. Been running about two years now. It’s my showpiece, but I built it around fish health first, looks second. Tried to scape it like a riverbed - dragonstone, slate, some driftwood, jungle sections in the back, and a clear lane in the middle so it doesn’t just look like a wall of green.

The 110-gallon. Riverbed scape with dragonstone, driftwood, and way too much water wisteria.

Plants: water wisteria everywhere. And I mean everywhere. It grows stupid fast, forgives mistakes, and actually does work for water quality instead of just sitting there looking pretty. Also got a red tiger lotus that blooms sometimes, some ferns I can’t kill, and duckweed on top because apparently that’s my life now.

Water wisteria. It grows stupid fast and does actual work for water quality.

If you’re new and reading this, don’t treat this as a shopping list. It’s more like... a stability list. Everything here either makes the tank more forgiving or makes maintenance easier to actually do.

What I’m running on the 110

110-gallon UNS rimless with the matching stand. Looks clean. Cost too much. Don’t regret it.

Pool filter sand for substrate. Cheap, classic. Plus a bunch of dragonstone, slate, and driftwood I probably overpaid for at the LFS.

Plants are already covered: water wisteria (aggressive), tiger lotus (dramatic), ferns (indestructible), duckweed (mistake that I’ve accepted).

For filtration I overbuild on purpose because it makes the big tank way more forgiving. Sponge filter - simple, never breaks, just rinse it in tank water. Fluval 407 canister doing most of the work. Spray bar on the output so I’m not creating a hurricane. Plus a bubble bar for extra oxygen because I like bubbles.

Spray bar setup. Spreads flow instead of creating a hurricane in one corner.(Yes, I have it lower than normal on purpose, ask me why)

The tank’s deeper than most standard setups, so I had to get air pumps rated for deeper tanks. Otherwise your sponge filter just sits there looking like it’s working while doing absolutely nothing.

Two 400W heaters set to 76°F. Running two keeps things consistent and if one dies I’m not scrambling.

Two Finnex planted lights on a timer. I run about 8 hours - well, 7.5 now because I kept forgetting to update the schedule after I shortened it during an algae outbreak last month. Also do a 30-minute sunrise/sunset ramp because it looks nice and the fish seem less freaked out.

I originally doubled up the lights because I wanted enough punch to reach the bottom of a deep tank. Looking back, I should’ve just bought one better light instead of two pretty-good ones.

Phoenix tap water. Heavily treated municipal supply. I always use conditioner because I’m not gambling with fish lives to save $12 a year. On the big tank I dose the whole tank before I start filling, then just run the hose. It’s easier than trying to dose 30 gallons in a bucket.

Food is a mix. Dry staple most days. Frozen brine shrimp and bloodworms as treats. I feed once a day, sometimes skip a day. Fish will act like they’re starving 24/7. They’re liars.

What actually keeps it stable

You can’t buy your way out of bad fundamentals. The tank cares what you do every week, not what you spent.

Get plants. Even easy ones. I don’t care if it’s just anubias zip-tied to a rock - put plants in there. Floaters especially. They suck up nitrates and make everything calmer.

Stock slowly. Painfully slowly. Add 3-5 fish, wait two weeks, check parameters, add more. I know it’s boring. Do it anyway.

Stop overfeeding. This is where everyone screws up, including me. Most mystery problems trace back to food rotting somewhere you can’t see. If the fish look hungry, they’re fine. They’re designed to look hungry.

When something goes wrong, I don’t start shopping for fixes. I figure out what I did wrong and stop doing it.

The routine (unglamorous and effective)

Daily: Feed. Watch the tank. That’s not a chore - that’s literally the point of having fish. I look at it from different angles because you catch stuff early that way. Wipe water spots off the rimless glass if they’re bugging me. Make a mental note if the wisteria is trying to conquer the entire tank.

2-3 times a week: Top off for evaporation. Arizona problems. Open-top rimless tank problems. It is what it is.

Once a month (ish): Clean the filters. And by “clean” I mean rinse the sponge and media in old tank water during a water change, pull out the gunk that’s blocking flow, put it back in. I don’t replace media unless it’s literally falling apart. That’s where your bacteria live.

When something looks wrong

I used to panic. Now I just run the checklist.

Check flow first. Is something clogged? Is there a dead spot?

Test ammonia, nitrite, nitrate.

Do a water change - even if the numbers look fine, it usually buys you time to figure out what’s actually wrong.

Then watch symptoms. Are they breathing hard? Flashing? Not eating? Hanging at the surface?

Lighting (how I stopped fighting algae)

Normal schedule: 7.5 hours of full light with a 30-minute ramp up and down. Then about 1.5 hours of blue “moonlight” at night because I think it looks cool. That’s for me, not the plants.

When algae starts showing up, I don’t run to the store for a magic bottle. I shorten the light schedule - drop to 6 hours if it’s bad. Lower intensity if I can. Manually scrub what I can reach. And check for dead spots in flow.

Dead spots are the sneaky problem. If you see debris settling in the same corner, or plants not moving, or algae always coming back in one spot - that’s flow, not light. Adjust the spray bar. Move some hardscape. Trim dense plant sections. Add a small airstone.

Most of my early mistakes were predictable: too many hours, too much light for the plants I actually had, and completely ignoring water movement.

Stuff I wasted money on

I’m not saying don’t buy gear. Just don’t buy it before you know you need it.

“Instant clear water” additives like Accu-Clear or Clarity. Cloudy water has a cause. Fix the cause. The bottle just masks it for three days and then it comes back.

Replaceable cartridge filters. You’re literally throwing away your biofilter every month on a schedule. It’s a subscription model for your bacteria.

Fancy biomedia. People will tell you Matrix or Seachem Pond Matrix or De*Nitrate is the key to everything. It’s usually not. Sponges and ceramic rings work fine.

CO2 injection before you can keep easy plants alive without drama. CO2 is great. It can also turn into a part-time job real fast.

Aquascaping tool kits on day one. Curved scissors, long tweezers, all that stuff in the YouTube videos. Buy tools when you actually need them, not because the unboxing looked satisfying.

Lily pipes and glass intake/outflow. They look fantastic on rimless tanks. They’re also fragile, expensive, and optional. Standard tubing works.

Your tank doesn’t care about expensive gear. It cares if you show up.

Water changes without dying

I try to hit 25% weekly unless something’s wrong, then I do more.

My current method is running a hose from outside through the back door. It’s as janky as it sounds. And I use an old wheeled cooler so I’m not hauling 5-gallon buckets like it’s CrossFit.

My water change setup. I run a hose from outside through the back door. Janky but it works.

Before this house I lived in a condo and used a sink attachment - basically a faucet adapter that let me hook up a hose and reach the tank. The method doesn’t matter. What matters is making it easy enough that you’ll actually do it every week instead of “planning to do it” for three weeks straight.

That’s it

If you want a tank that looks good and stays stable: build a system you can actually maintain.

Get plants. Stock slowly. Feed less than you think you should. Keep the water moving. Do water changes. The rest is just options.