Algae ID: What's Growing in Your Pond?

1 Filamentous algae gets its name from it's thread-like appearance. These filaments can be simple (unbranched) or complex (branched), forming mats or tuffs in water.

2 Pithophora algae has a coarse, cotton or wool like texture. It has extensively branched filaments giving it a bushy appearance.

3 Microcystis (often called blue-green algae) forms irregular colonies of many tiny cells clustered together. They consist of gas-filled structures that allow it to float.

4 Euglena is very distinguishable from its red appearance. This algae moves using a flagellum which makes it motile, unlike most algae that are attached or float passively.

What Kind of Algae Is in Your Pond? A Guide to Common Algae Types
Algae are a normal and natural part of every freshwater ecosystem. In fact, most algae serve important ecological roles like producing oxygen and forming the base of the aquatic food web. However, when conditions become unbalanced, especially when excess nutrients like phosphorus and nitrogen are present, algae can grow out of control and turn your lake or pond into a murky, green mess.

Not all algae are the same, and knowing which type you're dealing with is the first step toward responsible and effective management. Whether your concern is water quality, pond appearance, or ecosystem health, understanding the common algae types can help you make smarter decisions.

1. Planktonic Algae (Free-Floating Algae)
Planktonic algae are microscopic and suspended throughout the water column, often giving water a green, cloudy, or pea soup-like appearance. These are the algae most associated with widespread blooms.

 Management Tips: 

• Nutrient control is key, especially reducing phosphorus. Avoid phosphorus-based fertilizers near shorelines and divert stormwater runoff when possible.

• Install native shoreline vegetation to trap and filter nutrients before they reach the pond.

• Use phosphorus-binding agents to inactivate excess nutrients already in the water.

• Algaecides, when used, should be professionally applied and paired with aeration or biological tools to avoid oxygen crashes during algae die-off.
  

 2. Filamentous Algae (String Algae or Pond Scum)
This algae forms long, hair-like strands that grow on surfaces and float to the surface in dense mats. It thrives in shallow, nutrient-rich areas and is often the most visible and frustrating type for pond owners.

 Management Tips:

• Manually remove smaller infestations to prevent further nutrient recycling from decomposing algae.

• Install diffused aeration to boost oxygen and discourage stagnant zones.

• Add beneficial bacteria to break down muck and reduce available nutrients.

• Target dense mats with a professional algaecide application, and always combine with long-term nutrient reduction and circulation improvements.
  

 3. Blue-Green Algae (Cyanobacteria)
Technically a bacteria, not a true algae, cyanobacteria often form harmful algal blooms (HABs) that may produce dangerous toxins. These blooms can pose risks to people, pets, livestock, and wildlife.  

 Management Tips:

• Limit nutrient loading by preventing fertilizer runoff, managing animal access, and maintaining nearby septic systems.

• Install or enhance aeration to reduce stagnant, low-oxygen zones that favor cyanobacteria.

• Use phosphorus-binding products to limit available nutrients in both water and sediment.

• Apply algaecides cautiously and only by licensed professionals. Misuse, especially of copper-based products, can harm fish and beneficial microbes. Accurate identification of the cyanobacteria strain and risk level is essential before treatment.

 4. Attached Algae (Periphyton)
Periphyton refers to algae that grow on submerged surfaces such as rocks, plants, and docks. In moderate amounts, they are beneficial, contributing to nutrient uptake and serving as food for aquatic invertebrates.

 Management Tips:

• Manage overhanging vegetation to allow appropriate light levels and discourage overgrowth.

• Trim or thin aquatic plants to reduce the surface area available for algae to colonize.

• In high-visibility or recreational areas, manually remove algae from structures like docks or fountains as needed.

Algae Identification and Monitoring
Proper identification can help prevent overreaction or mistreatment:

• Visual clues such as color, texture, and growth location (floating, submerged, or attached) can guide initial assessments.

• Perform regular water testing for phosphorus, nitrogen, and oxygen to detect nutrient imbalances before blooms occur.

• Seasonal monitoring helps catch early signs of overgrowth, keeping management costs and risks lower over time.
  

A Smarter Approach to Algae Control
Algae aren’t inherently bad, they’re part of a healthy pond. But when nutrient levels become unbalanced, algae can grow excessively, creating visual, ecological, and recreational problems.

While algaecides, when applied by licensed professional, can be a helpful tool, they’re just one piece of the puzzle. The most effective, long-term solution is proactive, preventable lake and pond management. With regular monitoring, nutrient control, and aeration, you can maintain a healthy, balanced aquatic environment and minimize the need for reactive treatments, keeping your pond beautiful, heathier and more enjoyable all season long.

Contact Jones Lake Management today to schedule a site visit or request an algae control plan tailored to your waterbody’s needs.

About Jones Lake Management

Since 1949, Jones Lake Management has been a trusted leader in lake and pond management, delivering scientifically backed solutions to create and maintain healthy, balanced, and beautiful waterbodies. Our expert team offers a full range of services, including fish stocking, fisheries management, water quality monitoring, algae and aquatic weed control, aeration solutions, erosion control, invasive species management, hydraulic dredging, and more. Whether you manage a private lake, an HOA stormwater pond, a golf course water feature, or a municipal waterway, we provide customized solutions to ensure your waterbody remains healthy, functional, and thriving.

Discover our trusted lake and pond management partners nationwide—bringing expertise and care to communities across the country. From Aqua Services and Pond Lake Management in the Southeast, to Water and Wetland in New England, Savin Lake Services in Michigan, Wisconsin Lake and Pond Resource in Wisconsin, Aquatics Associates in Colorado, and Clear Water, Johnson Lake Management and Aquatic Features in Texas, each partner delivers premier service tailored to their region. Visit us at www.joneslakemanagement.com