Common Spring Pond Problems

(and How to Fix Them)

Common spring pond problems often appear as ponds wake up after winter, with rising temperatures and longer daylight hours affecting water quality, fish behaviour, and plant growth.

Spring is when ponds truly come back to life. As water temperatures rise and daylight increases, fish become more active, plants begin to grow, and filtration systems return to full use. However, this seasonal shift can also bring a few common pond problems — especially after winter dormancy.

The good news? Most spring pond issues are completely normal and easy to resolve with the right approach. Below we cover the most common problems pond owners face in spring, why they happen, and what you can do to fix them.

Blanketweed & String Algae

What you might notice:

Long green strands clinging to plants, rocks, waterfalls, or floating just under the surface.

Why it happens in spring:
During winter, pond plants slow down or die back, while nutrients from fish waste and decaying debris build up. As sunlight increases in spring, algae can take advantage before plants catch up.

What helps:

Manually remove as much blanketweed as possible using a net or brush
Reduce excess nutrients by clearing debris and sludge
Check filtration is running efficiently
Use a blanketweed treatment or UV system if required

A small amount of algae is normal, but controlling it early prevents bigger problems later in the season.

Barley straw can also be a useful preventative tool. As it breaks down slowly in the pond, it releases natural compounds that help inhibit algae growth. Barley straw works best when:

Used early in the season
Placed in areas with good water flow
Combined with good filtration and regular maintenance

It’s not an instant fix, but it can be very effective as part of a long-term algae control strategy.

👉 Read our full guide to Blanketweed and Algae

Green or Cloudy Pond Water

What you might notice:

Water that looks green, hazy, or murky rather than clear.

Common spring causes:

Microscopic algae blooms triggered by sunlight
Organic waste breaking down after winter
Filtration not yet fully established

What helps:

Test your pond water to identify nutrient or pH issues
Ensure your filter and pump are clean and correctly sized
Avoid overfeeding fish during early spring
Consider a green water treatment or UV clarifier if clarity doesn’t improve

Green water often clears naturally as plants and beneficial bacteria become established.

👉 Read our full guide to Green Water in Ponds

Duckweed & Floating Pond Plants

What you might notice:

A layer of tiny green floating leaves quickly spreading across the pond surface, sometimes covering large areas in a short space of time.

Why duckweed appears in spring:
Duckweed thrives in nutrient-rich water with low surface movement. After winter, ponds often contain excess nutrients from decomposing leaves and waste, creating perfect conditions for duckweed to multiply as soon as temperatures rise.

What helps:

Remove duckweed manually using a fine net (regular removal makes a big difference)
Improve water circulation — duckweed prefers still water
Reduce nutrient levels by clearing debris and avoiding overfeeding
Encourage healthy plant growth to compete for nutrients

Duckweed isn’t harmful in small amounts, but if left unchecked it can block light and reduce oxygen levels, so early control is best.

👉 Read our full guide to Duckweed in Ponds

Fish Acting Sluggish or Hiding

What you might notice:

Fish staying near the bottom, hiding, or showing little interest in food.

Why this is common in spring:
Fish metabolisms are still adjusting to fluctuating temperatures. Cold nights combined with warmer days can cause stress, especially if water quality isn’t ideal.

What helps:

Avoid feeding until water temperatures are consistently above 10°C
Test water for ammonia and nitrite, especially after winter
Improve oxygen levels with good water movement
Avoid adding new fish until the pond is stable

Slow behaviour early in spring is normal — it usually improves as conditions settle.

Surface Scum, Foam or Floating Debris

What you might notice:
A thin film on the water surface or light foam around waterfalls and returns.

Why it appears:
Proteins released from decaying organic matter, fish waste, and early feeding can collect at the surface, especially if circulation is low.

What helps:

Remove dead leaves and plant matter
Improve surface movement and aeration
Reduce feeding temporarily
Check pumps are correctly positioned

Surface issues are usually short-lived once the pond is properly cleaned and flowing again.

Filters or Pumps Not Performing Properly

What you might notice:
Reduced water flow, noisy pumps, or filters overflowing.

Why it happens:
Over winter, sludge, leaves, and debris can settle inside pumps and filter media. When systems are restarted, blockages quickly become apparent.

What helps:

Thoroughly clean pumps, impellers, hoses, and filter media
Check seals, pipework, and electrical connections
Restart filtration gradually to avoid shocking beneficial bacteria

Spring is the ideal time to service equipment before fish activity increases.

👉 Read our full guide to Pond Filter Problems

A Simple Spring Pond Care Checklist

Before the season gets into full swing:

Remove leaves, sludge, and dead plant matter
Clean and restart filtration systems
Test pond water parameters
Resume feeding slowly and only when temperatures allow
Add beneficial bacteria to support filtration

These simple steps make a huge difference to pond health throughout the year.

Need Help Getting Your Pond Ready?

Spring pond problems are normal — but with the right advice and products, they’re easy to manage.

At Birchwood Aquatic Centre, we stock a full range of pond fish, filters, treatments, pumps, and accessories, and our experienced team is always happy to offer honest, practical advice.

If you’re unsure what your pond needs this spring, bring in a water sample or pop in for a chat — we’re here to help you enjoy a healthy, clear pond all season long.