Worst Fish for Planted Tanks: Species That Dig, Eat and Destroy

Table of Contents

• Why Some Fish Destroy Plants
• The Plant Eaters
• The Diggers and Uprooters
• The Grazers That Cause Damage
• Destructive Species and Their Alternatives
• Frequently Asked Questions

Why Some Fish Destroy Plants

Not every fish belongs in a planted aquarium. This is a lesson many hobbyists in Singapore learn the hard way, often after investing hundreds of dollars in premium aquascaping plants, only to watch them get demolished in a matter of days.

Fish destroy plants for three main reasons. Some are genuinely herbivorous and see your carefully cultivated stems as food. Others are diggers that rearrange substrate as part of their natural behaviour, uprooting anything in their path. A third category are large, powerful fish that cause collateral damage simply by being too big and boisterous for a planted environment.

Understanding why certain species are incompatible with planted tanks helps you make better stocking decisions from the start. If you already have one of these fish and want to keep plants, we will also suggest alternatives that give you similar appeal without the destruction.

The Plant Eaters

Goldfish (Carassius auratus)

Goldfish are perhaps the most notorious plant destroyers in the hobby. They are omnivorous with a strong preference for vegetation, and they eat virtually any aquarium plant you put in front of them. Anubias, Java fern, vallisneria, stem plants, floating plants: nothing is safe. They also produce enormous amounts of waste relative to their size, which further complicates planted tank maintenance.

Beyond eating plants, goldfish are coldwater fish that prefer temperatures of 18-22 degrees Celsius, making them a poor fit for Singapore’s ambient water temperature of 28-32 degrees Celsius. Keeping goldfish in tropical conditions shortens their lifespan and stresses them significantly.

Plant-safe alternative: If you want a chunky, personable fish with character, consider honey gouramis. They interact with their owners, have distinct personalities and leave plants completely alone.

Silver Dollar (Metynnis hypsauchen)

Silver dollars are schooling fish related to piranhas, but instead of eating meat, they eat plants. They treat aquarium plants like an all-you-can-eat salad buffet. A group of silver dollars can strip a heavily planted tank bare within a week. They are efficient, thorough and relentless plant eaters.

They grow to around 15cm and need to be kept in groups, which means even more destruction. There is no plant species that is reliably safe from silver dollars.

Plant-safe alternative: For a silvery, disc-shaped schooling fish, try diamond tetras. They have a similar reflective quality and school well but are completely plant-safe.

Tinfoil Barb (Barbonymus schwanenfeldii)

Tinfoil barbs are a Southeast Asian native that grows to a massive 30cm or more. They are active, powerful swimmers that eat plants voraciously. Many hobbyists in Singapore buy them as small, attractive juveniles without realising how large they become and how destructive they are to planted setups.

In addition to eating plants, their size and activity level means they physically knock over and uproot anything in their path. A group of adult tinfoil barbs needs a tank of at least 500 litres, which rules out most home setups.

Plant-safe alternative: Cherry barbs offer the barb family’s active personality and attractive colouration at a fraction of the size, and they leave plants alone.

Buenos Aires Tetra (Hyphessobrycon anisitsi)

This is the planted tank wolf in sheep’s clothing. Buenos Aires tetras look like harmless community fish, and many are sold as such. However, they are one of the few tetra species that actively eat plants. They are particularly fond of soft-leaved species like cabomba and hygrophila, but will move on to tougher plants once the easy options are gone.

Plant-safe alternative: Cardinal tetras or rummy nose tetras offer similar schooling appeal with zero plant damage.

The Diggers and Uprooters

Oscar (Astronotus ocellatus)

Oscars are intelligent, charismatic fish that many hobbyists adore for their dog-like personalities. Unfortunately, they are also committed interior designers who constantly rearrange their tanks. They dig pits in substrate, move rocks, uproot plants and push decorations around.

Growing to 30cm or more, oscars have the physical power to completely rearrange a planted aquascape overnight. They do not eat plants, but the physical destruction they cause is just as thorough. Their massive waste output also makes maintaining planted tank water parameters extremely challenging.

Plant-safe alternative: If you want a fish with personality and intelligence, consider a pair of German blue rams or Apistogramma dwarf cichlids. They are interactive and characterful without the destruction.

Large Cichlids (African and Central American species)

Most large cichlids are enthusiastic diggers. African cichlids from Lakes Malawi and Tanganyika dig as part of their territorial and breeding behaviour. Central American cichlids like convicts, Jack Dempseys and firemouths also dig extensively. They excavate pits, pile substrate against tank walls and uproot any plant in their territory.

Even species marketed as “plant-friendly” cichlids, such as angelfish, can be problematic. While angelfish do not eat plants, large adults sometimes uproot smaller plants while foraging or defending breeding sites.

Plant-safe alternative: Dwarf cichlids like Apistogramma or kribs provide cichlid behaviour and breeding interest at a size that does not threaten plants. Minor digging may occur near breeding caves, but it is rarely destructive.

The Grazers That Cause Damage

Large Plecos (Hypostomus spp. and similar)

Common plecos grow to 30-45cm and are far too large and powerful for most planted tanks. While they primarily eat algae, their size means they bulldoze through plants while grazing. They also produce copious waste, which promotes algae growth, creating an ironic cycle where the algae eater causes more algae.

Many Singaporean hobbyists buy small common plecos as algae cleaners, not realising they will outgrow their tank within a year. A 5cm juvenile pleco from a local fish shop will eventually become a 35cm tank-wrecking machine.

Plant-safe alternative: Otocinclus catfish or nerite snails provide excellent algae control at a fraction of the size, with zero risk to plants. Bristlenose plecos (Ancistrus spp.) are also acceptable as they max out at about 12cm and are gentler on plants.

Destructive Species and Their Alternatives

Signs Your Fish Are Damaging Your Plants

Sometimes the damage is not immediately obvious. Watch for these warning signs:

• Bite marks on leaves – ragged edges or holes that are not caused by nutrient deficiency (deficiency holes are usually between leaf veins)
• Uprooted stems – plants floating at the surface that were previously planted
• Substrate craters – pits dug near plant bases
• Stripped stems – leaves missing from one side, suggesting fish are pulling them off
• Declining plant mass – overall plant volume decreasing despite good light, CO2 and fertilisation

If you notice these signs, identify the culprit by observing the tank at different times of day. Some fish are most destructive at dawn, dusk or during the night when you are not watching.

Can You Keep Destructive Fish With Any Plants?

If you already have a fish from the list above and want some greenery, your options are limited but not zero.

• Anubias tied to rocks or wood – tough leaves that most fish (except goldfish) leave alone, and no roots in substrate to uproot
• Java fern attached to hardscape – similarly tough and not planted in substrate
• Floating plants – out of reach of bottom-dwelling diggers, though surface feeders may still eat them
• Pothos or lucky bamboo with roots in water – the plant itself is out of the tank and only roots are submerged

However, these workarounds give you a decorated tank, not a true aquascape. If you want a genuine planted aquarium with carpets, stems and a full aquascape layout, you need plant-safe fish.

Frequently Asked Questions

My fish is not on the destructive list but is still eating my plants. Why?

Some fish nibble plants when they are underfed or when their diet lacks variety. Ensure you are feeding a balanced diet that includes both protein and vegetable matter. Blanched vegetables like courgette or spinach can satisfy plant-nibbling urges. Stress from poor water quality or overcrowding can also cause unusual behaviour, including plant destruction.

Can I keep goldfish in Singapore without a chiller?

It is not recommended. Singapore’s ambient water temperature of 28-32 degrees Celsius is significantly above goldfish comfort range. While goldfish can survive temporarily at these temperatures, long-term exposure reduces their lifespan and increases disease susceptibility. An aquarium chiller adds significant electricity cost and noise, making goldfish a poor choice for most Singaporean homes.

Are all tetras safe for planted tanks?

Most tetras are plant-safe, but not all. Buenos Aires tetras are well-known plant eaters. Serpae tetras occasionally nibble on fine-leaved plants. However, the vast majority of popular tetra species, including cardinals, neons, embers, rummy noses and glowlights, are completely safe for planted tanks.

What if I bought a destructive fish by mistake?

If you have recently purchased a fish that is incompatible with your planted tank, consider rehoming it responsibly. Some local fish shops in Singapore accept returns or trades. Online forums and local aquarium groups on Facebook and Carousell are also good places to find new homes for fish that do not suit your setup.

Looking for species that will complement your planted tank instead? Check out our guide to the best fish for a planted aquarium for 15 species that coexist beautifully with live plants.

Need help choosing the right livestock for your aquascape? At Gensou, we have over 20 years of experience creating custom planted aquariums with carefully selected species. Visit us at 5 Everton Park, Singapore, or contact us for a consultation.

Related Reading

• Aquarium as Home Décor: Placement, Styles and Design Tips
• Aquarium Background Ideas: Paint, Film, 3D and Natural
• 10 Beginner Aquarium Mistakes and How to Avoid Them
• Top Aquarium Mistakes in the First Month and How to Avoid Them
• Monthly Aquarium Cleaning Schedule: What to Do and When