You know that feeling when you’re standing in a pet store, surrounded by empty glass boxes, and somehow they all look identical? I used to think picking an aquarium was like choosing a picture frame – just grab something that fits your space and looks decent. Then I killed my first entire tank of fish and learned that, oh wow, this decision actually matters. A lot.
This was maybe five years ago, back when I thought a 5-gallon cube could handle whatever I threw at it. I crammed six neon tetras, a betta, and some cherry shrimp into this tiny thing because the internet said “small tanks are perfect for beginners!” Spoiler alert: they’re really, really not. I woke up one morning to find my neon tetras gasping at the surface while my water test strips showed ammonia levels that could probably strip paint.
That expensive lesson taught me something important – your tank choice affects literally everything that happens afterward. It’s like… choosing an apartment. You can have the most gorgeous furniture in the world, but if your place is too small or poorly laid out, you’re gonna have a bad time. Same deal with aquariums, except your mistakes kill fish instead of just making you cranky.
I’ve set up probably fifteen tanks at this point (don’t tell my boyfriend the exact count), and I’ve made pretty much every rookie mistake possible. Bought tanks that were too shallow, too tall, too small, wrong shape, wrong material… basically if there’s a way to mess up tank selection, I’ve done it. And honestly? Some of my most expensive failures taught me the most important lessons.
Size is where most people screw up first. I get it – small tanks seem easier, cheaper, take up less space. But here’s the thing about water chemistry: it’s way more forgiving when you have more water to work with. Think about it like cooking. If you add too much salt to a tiny cup of soup, it’s ruined. Add the same amount to a huge pot? Barely noticeable.
My current smallest tank is six gallons, and that’s only because I’ve been doing this for years and test my water obsessively. When people ask me what size to start with, I always say twenty gallons minimum. Yeah, it costs more upfront. Yeah, it takes up more space. But you know what costs even more? Replacing dead fish every few weeks because your tiny tank can’t handle normal beginner mistakes.
I learned this lesson the hard way with my second tank – another five-gallon disaster, this time with a fancy goldfish. (I know, I know, goldfish need way more space than that. Young me was an idiot.) That poor fish lasted maybe three months before the water quality issues caught up with him. Moved to a twenty-gallon after that and suddenly keeping fish alive became… actually possible.
Then there’s the whole shape thing, which gets way more complicated than you’d expect. Those gorgeous shallow tanks you see in aquascaping competitions? They look amazing in photos but they’re basically expert mode for tank keeping. I tried one once – this beautiful rimless rectangle that was maybe six inches tall but super long and wide. Looked incredible with a carpet of Monte Carlo and some dragon stone.
Also nearly drove me insane trying to maintain it. The water temperature swung wildly because there wasn’t much volume to buffer changes. CO2 levels were impossible to keep stable. And don’t even get me started on trying to photograph it without getting reflections of my ceiling fan. After six months of fighting with that thing, I swapped it for a boring old standard rectangle and my stress levels dropped immediately.
Standard rectangles are popular for good reasons. They’re easier to heat evenly, simpler to light, give fish actual swimming space, and – this matters when you’re furnishing a tiny apartment on a QA tester’s salary – they’re way cheaper than fancy designer shapes.
That said, I do have a couple non-standard tanks that work well for specific purposes. There’s a tall cube in my bedroom that’s perfect for my angel fish setup. Lots of vertical space for the angels to show off, room for tall plants like vallisneria, and it fits in the corner without taking over the whole room. The downside? Cleaning the bottom requires me to basically stick my entire arm in the tank, and I’ve definitely gotten more aquarium water on my floor than I care to admit.
I’ve also got this long, shallow bookshelf tank on my desk at work – it’s maybe three gallons total but spread out over like eighteen inches. Terrible for most fish, but perfect for cherry shrimp and some moss. Sometimes the weird shapes work, but you have to know what you’re getting into.
Material choice is another rabbit hole entirely. Most tanks are either regular glass, acrylic, or the fancy low-iron glass. Regular glass is fine – it’s what most of my tanks are made of. Heavy as hell (moving my 40-gallon required bribing two friends with pizza), but durable and doesn’t scratch easily. The green tint on thick glass edges bothers some people, but honestly after a week you stop noticing it.
Acrylic is lighter and insulates better, which is nice in my drafty apartment. But oh my god, it scratches if you look at it wrong. I have an acrylic tank that I’ve somehow managed to scratch even though I’m super careful with it. Paper towels will scratch it. Some algae scrapers will scratch it. I’m pretty sure aggressive thoughts will scratch it. The scratches catch the light and make the whole tank look cloudy, which drives me absolutely nuts.
The fancy low-iron glass is gorgeous – crystal clear, no green tint, looks like the water is just floating in mid-air. I have one rimless low-iron tank and the clarity is incredible. Also costs about three times what a regular glass tank costs, so it’s definitely a “treat yourself” purchase rather than a practical choice for most setups.
Speaking of rimless tanks… they look super modern and clean, photograph beautifully, but they’re not necessarily better than rimmed tanks. The rim actually serves a purpose – it makes the tank stronger and gives you somewhere to clip equipment. Plus if you have pets, the rim provides a tiny bit of protection against curious paws. My cat learned this the hard way when he tried to drink from my rimless tank and got an unexpected swimming lesson.
One thing nobody talks about enough is glass thickness. This sounds boring and technical, but I learned why it matters when a friend’s tank developed a slow leak from the bottom seam. Turns out the glass was too thin for the size of the tank, so the bottom was flexing slightly until the silicone seal gave up. Fifty gallons of water on hardwood floors is not a fun cleanup project, trust me.
The thickness requirements scale with tank size – bigger tanks need thicker glass or they’ll bow and eventually fail. Most reputable manufacturers get this right, but those super cheap tanks on Facebook Marketplace? Sometimes they cut corners in ways that’ll cost you later.
I get asked a lot whether certain tank shapes work better for different types of aquascapes. There’s some truth to this, but it’s not as rigid as some people make it sound. My Dutch-style planted tank works great in a standard rectangle because I can create depth with plant placement. The Iwagumi-style tank with just rocks and carpet plants looks better in a shallower, wider format because you can really see the rock arrangement.
But honestly? Most aquascapes can work in most reasonable tank shapes. It’s more about working with what you have than finding the “perfect” dimensions.
The real question you should ask yourself is: what fits your actual life? The most beautiful tank in the world becomes a chore if it needs more maintenance than you can realistically provide. When I was traveling constantly for work, I simplified everything – hardier fish, fewer plants, basic equipment. Now that I’m home more, I can handle the high-tech planted tanks with daily CO2 adjustments and weekly plant trimming.
My current collection ranges from a basic 20-gallon with a hang-on-back filter and plastic plants (don’t judge, it houses my oldest fish and he’s happy) to a rimless planted tank with automated CO2, fancy lights, and substrate that cost more per pound than my grocery budget. Each one serves its purpose, and each one taught me something different about what works and what doesn’t.
The perfect tank isn’t the one that wins contests or gets the most Instagram likes. It’s the one that fits your space, matches your maintenance schedule, works with your budget, and makes you happy to look at every day. Everything else – the fish, the plants, the fancy equipment – that all comes after you get the foundation right.
So yeah, I spend way too much time researching tanks before buying them now. But considering how much money and heartbreak I could have saved myself by making better choices upfront… totally worth being that person who reads specs and reviews for hours before purchasing a glass box.
Priya proves aquascaping doesn’t need deep pockets or big spaces. From her San Jose apartment, she experiments with thrifted tanks, easy plants, and clever hacks that keep the hobby affordable. Expect honest lessons, DIY tips, and a lot of shrimp in tiny jars.
